As for designs, I like tents that have the door either at the front (usually, the higher end of the tent), or that have two doors, one on each side of tent or either side of the high end. The latter configuration is a bit more convenient, as you can reach things in the vestibule while still lying in your sleeping bag, a bonus for lazy people like me.
But what tent? My first choice probably would be the new Marmot Aeolos 2P ($325; www.marmot.com), available from April 25. Marmot tents are absolutely first-rate, with excellent design and construction. The Aeolos is no exception, with lots of head and elbow room thanks to poles designed to create near-vertical sidewalls. Its floor is 90 inches long, so there's room for you to stretch out. Doors on either side of the head end allow easy access to the twin vestibules. And it's both well-ventilated and very rain- and wind-proof. Weight, at five pounds, five ounces, is pretty good for this much tent. Put in your order now!
For a bit less money, the Sierra Designs Reverse Combi ($250; www.sierradesigns.com) is another solid choice, a tent that has room for a tallish guy like yourself, with lots of headroom as well. Doors are on each side, and centered in the sidewall. Big twin vestibules and excellent ventilation make the Reverse Combi a real bargain.
Still, if this were my trip, I'd be sorely tempted to pack in a Black Diamond Lighthouse ($369; www.bdel.com). This is a single-wall tent made with Epic Nextec, a fabric that is highly breathable and generally water-resistant. What that means is that if it rains for a day or two, a little moisture might creep in. But you're far more apt to see thunderstorms, and it can resist those easily. Plus it weighs only three pounds, and for a big trip, weight certainly is an issue. There are two downsides: One, it has just one side-opening door; two, it doesn't have a vestibule (one can be added for $139, but that also adds weight). Still, it's a great tent for a trip such as yours.
For more expert reviews of the best shelters, check out Outside Online's Tents Buying Guide.