And I mean all-synthetic, undergarments included. Patagonia's seamless Capilene Briefs ($18; www.patagonia.com) and Capilene Mesh Bra ($35) would be a good start. Over those, a warm-weather T-shirt such as REI's MTS Lightweight Crew ($24; www.rei.com) has polyester fabric that dries very fast. This will be comfortable across a wide temperature range so makes a good base layer if it's chilly, plus will work fine by itself when very warm. I'm not a huge fan of "convertible" pants, but Ex Officio's Buzz Off Convertible Pant ($79; www.exofficio.com) offers good sun protection, a bug-repelling fabric finish, and that option of shorts or long pants. And they're made of a light nylon that dries quickly.
Layer over that a light fleece jacket such as Marmot's Reactor Full Zip Jacket ($75; www.marmot.com). And a rain shell of some sort; REI's Taku ($189; www.rei.com) is one fantastic option in this department.
For footwear, you'll clearly want some sort of aqua-ready shoe, such as the Salomon Techamphibian ($80; www.salomonoutdoor.com), which has high-traction outsoles, fast-drying uppers, and drain holes to let water escape quickly. Better, I think, than a sandal-type shoe, as sand can get under the sandal straps and quickly chafe. I'd pack some inexpensive tennis shoes to wear around camp in the evening.
Read Away.com's guide to climbing and canyoneering for more gear to carry you safely through the slots.