Hands-down the best way to see the country is to rent a sweet RV, especially for longer trips. Unlike in the U.S., where RVs are often corralled into concrete "parks," New Zealand has a "freedom camping" ethos. That means you can pull off the road almost anywhere, as long as your rig has a toilet on board and you're not in a city or the restricted zone of a national park. RVs also make great rolling gear garages (kayaks, bikes, packs, raingear ...), and having a refrigerator means you can cook green-lipped mussels at sunset. Two planning suggestions: prepare mentally to drive a large vehicle on the left side of the road, and budget for a pit stop or two at one of New Zealand's legendary lodges.
If you have three or more weeks, it's worth touring both islands. Most international flights land in Auckland, and if you head (mostly) south from there, it's roughly 1,200 miles and a half-dozen climates—from subtropical coast to high-alpine glaciers—to Fiordland National Park. But a truly epic adventure might have you logging 2,500 miles or more. On the North Island, spend some days on the Pacific Coast Highway, lazing on the beaches of the Coromandel Peninsula or surfing the beach breaks in Tauranga. Turn inland on Highway 33 and hit Rotorua's famous hot springs and mountain-bike trails. Eventually you'll want to roll through the Hawke's Bay wine country to Wellington, the antipodean San Francisco and port for the Interislander Ferry, which crosses Cook Strait in three hours (prices vary by vehicle; interislander.co.nz).
The road tripper's route on the South Island is Highway 6 along the wild west coast and the Tasman Sea. It's oceanside car camping out there and an easy three days to the Franz Josef and Fox glaciers (guided glacier walks at both spots; franzjosefglacier.com and foxguides.co.nz). Inland over the Haast Pass is the adrenaline-sports capital of Queenstown, the birthplace of commercial bungee jumping and guided canyoneering adventures (see "Get Amped"). You could play here for a week, but it's worth cruising farther down the island to Fiordland National Park, where the road dead-ends at Milford Sound and sheer rock faces plunge into an inlet full of whales, seals, penguins, and dolphins.
Your RV provider: United Campervan (campervan.co.nz), which has a wide selection of models (daily prices vary depending on the season and vehicle), or Christchurch-based Natural High, which offers RVs and any combination of kayak, bike, and camping-gear rental (naturalhigh.co.nz).
The "wilderness lodge" here has been elevated to a high art form, with a price to match, though the cost is often offset somewhat by the inclusion of meals. The offerings range from classic genteel oases to slick 21st-century adventure hubs, with square-jawed guides, 500-bottle wine lists, and heli-everything.
The North Island's Huka Lodge is the archetype of the former category. What started out as a fishing camp in 1924 has become so discreetly luxurious, with its private suites on the Waikato River, 17 perfectly manicured acres, and alfresco five-course dinners, that Queen Elizabeth II and Barbra Streisand have been known to relax here (suites from $590 per person, including breakfast and dinner; hukalodge.co.nz).
Across the North Island and at the opposite end of the taste spectrum is Ahu Ahu Beach Villas, on the Taranaki Peninsula. This is actually a cluster of rustic villas set right on a black-sand beach with a killer view of 8,261-foot Mount Taranaki and immediate access to the local café scene and exhilarating wilderness walks. A handful of New Zealand's best surf breaks are within a 20-minute drive (villas from $160 per night; ahu.co.nz).
On the South Island, the adrenaline-sport scene in Queenstown has spurred a proliferation of lodges. One of the most consistently recommended is Blanket Bay, on the shores of Lake Wakatipu, 45 minutes north of Queenstown. Fly-fish, flight-see over Fiordland National Park, and dine in the wine cave while drinking local varietals (doubles from $750; blanketbay.com).
Or go ape on the South Island's Pacific coast in the Hapuku Lodge & Tree Houses. The one-bedroom retreats, 30 feet off the ground in a manuka grove, are quintessentially Kiwi—chic, stark, and ecologically correct—and each features a wood-burning fireplace and a couples bath. The Tarzan & Jane Tree House Retreat includes a one-night stay, a bottle of champagne, dinner, and breakfast ($1,015 per couple; hapukulodge.com).
Tramping in New Zealand is like a national religion. The nine multi-day hut-to-hut Great Walks are exceptional and, thanks to Department of Conservation vigilance, often blissfully uncrowded. The Milford Track, a 33-mile route weaving through alpine terrain overlooking deep-walled fjords in the far south, gets the most buzz—and deserves it. The four-to-five-day trek starts with a boat journey across Milford Sound. Your first view: 5,551-foot Mitre Peak, jutting straight out of the water. The track climbs a 3,507-foot pass across ice fields, skirts 1,904-foot Sutherland Falls, and ends with another boat ride, across Lake Te Anau. You can reserve hut space, plus bus and boat tickets, for the November-to-April trekking season on the DOC Web site (roughly $340 for huts and transportation; doc.govt.nz).
The 34-mile Abel Tasman Coast Track is tramping lite. It's sunnier here on the north end of the South Island, the beech forests are interspersed with golden-sand beaches, the maximum elevation is less than 700 feet, and you're more likely to find an impromptu campsite party with Danes and Germans than wilderness solitude. Beware: there are two low spots along the trek—Onetahuti and Awaroa—where high tides can cover the trail, so be sure to time it right. For your nights on the trail, choose from four huts ($27 per person) or 18 primitive campsites ($9 per person).
An alternate to the Great Walk circuit is Aspiring Guides' (aspiringguides.com) eight-day Gillespie Rabbit Pass Traverse, in Mount Aspiring National Park, about midway down the South Island. The longest guided trek in New Zealand, it cuts through everything from rainforests to hanging glaciers. Plus you can brag that you tagged the icy shoulder of Mount Awful (the treacherous summit is 7,201 feet). The guides double as camp cooks, and you stay in pre-pitched campsites and luxury mountain huts (from $1,830 per person).
New Zealand has 9,400 miles of coastline plus hundreds of freshwater lakes and more than 125 whitewater rivers. Sailors blow around Auckland. Surfers kick back in funky Raglan. Whitewater paddlers gather on the South Island's west coast, where milky Class V (and lesser) rivers rush to the Tasman Sea. Sea kayakers cruise all over. Which is to say, there are options.
An aggressive way to start: crewing a three-hour head-to-head sailing race on the retired 80-foot America's Cup yacht NZL 41 in Auckland's Waitemata Harbor ($150; explorenz.co.nz). For longer cruising adventures, the Bay of Islands, the archipelago off the northeast coast of the North Island, has summer temps in the high sixties and seventies, steady breezes, and some 150 islands with safe harbors. Great Escape Yacht Charters rents Davidson 20's ($90 per day) or Noelex 25's ($120 per day; greatescape.co.nz).
Surfing in New Zealand means packing a 5/3 wetsuit and, if you're after serious swell, coming in the winter (April to June). Bring your shortboard and drop in on Raglan (on the west coast of the North Island), home to "the longest left in the world," which is actually a series of three left-hand point breaks that jut from the foot of a dormant volcano. Crash at Solscape (close to hot spots Manu Bay and Ngarunui Beach), a beach house made completely from recycled timbers and native bricks (studios from $105; solscape.co.nz).
Starting a rafting trip in a helicopter generally leads to good things. Hidden Valleys offers two-day trips on the Class V Perth and Class III–IV Whataroa rivers. You'll fly to a gentle stretch of the snow-fed Perth, then drop steep gorges through temperate rainforest before flying to the put-in of the Whataroa, which offers Southern Alps views on the descent to the west coast ($670 per person; hiddenvalleys.co.nz).
Sea-kayaking Milford Sound is a classic Kiwi adventure, but nearby Doubtful Sound, in Fiordland National Park, is more than twice as long and much less visited, because getting there requires a 19-mile ferry ride across Lake Manapouri, followed by a 14-mile bus ride. Adventure Kayak & Cruise leads day trips and overnight outings past 722-foot Helena Falls and Commander Peak, which stands almost 4,000 feet over the water (from $182; www.fiordlandadventure.co.nz).
Fly-fishing here is serious sport. So much so that New Zealand has a nationwide ban on felt-soled boots, which spread microorganisms that can disrupt freshwater ecosystems. The quintessential Kiwi fishing experience is sight-casting dry flies in small, crystal-clear rivers for football-size brown trout. But it's not easy: only a handful of New Zealand rivers have more than 1,000 fish per square mile (as compared with western U.S. rivers, with counts as high as 20,000). A guide is essential, and most of the best are based out of high-end lodges.
Mike McClelland, owner of the Best of New Zealand Fly Fishing (bestofnzflyfishing.com), can customize any trip. Among his favorite spots is the North Island's Poronui lodge, a high-country estate surrounded by 25 miles of the choicest fishing in New Zealand. You can walk spring creeks, float wilderness rivers, or helicopter to remote streams (from $670 per person per night, including guides and meals; poronui.co.nz).