I've been thinking about buying a hammock but only for short weekend trips where ill be camping in the state forests where there are plenty of trees. Hammocks being lighter, whats the point of hauling heavy tent gear out for a short trip.
I guess it boils down to how long you'll be gone, if you're gone for a lenthy peroid of time id say bring the tent because who knows when you won't have trees to sling your hammock from. If you're gone for just a few days call the campsites you'll be at and just ask em i suppose. I'm unfamilliar with the GAP but hope to tour it some day, looks great. Have a fun trip!