Brad
If this is a one time trip or very occasional trip, don't go nuts. I've been to El Pescador twice (both in November). They have some limited loaner gear. Your normal lines/rods/reels will be fine. If you find out you enjoy the salt then by all means gear up for future trips. I got a grand slam on one trip and I didn't have $800 reels and tropical lines, just have plenty of backing and carry extra lines if possible. Good rods are necessary for dealing with wind. Bones are small, permit can be large, tarpon come as both babies (nature preserve) and big boys (Long Caye and the Savannah).
Enjoy
striper33