As a fellow floridian I feel your pain about nowhere really to train. I'm heading off from Springer somewhere between mid March and April 1... I'm a good 6'4'' 275 and built like an ox.. since south florida is lacking in hills, i've been hiking with a 20lb pack 2-4hrs on my days off up and down this landfill that has been turned into a park.. if the incline is hurting too much, i just take the trail around it with a more 'user friendly' grade to it... i'm sure they have similar parks in tampa...
the only thing im really worried about is finding a sleeping bag big enough that doesnt way 4-7lbs