welcome to florida. like you mentioned, you have Ocala National Forest north of you, Hardrock offroad park which is also north of you in Ocala, west of you is Citrus (Withlacoochee state forest), and then all the way on the east coast there is 5a if you want to go mudding. a few other small places in between.
if you have a facebook account check out florida4x4.org - a group (mostly in central FL) that sets up rides and talks ****. mnay other clubs around too...Orlando Jeep Club, Mid Florida Jeep Club..to name a few.
pretty much every weekend someone, somewhere is going wheeling, so just post up here or on florida4x4 if you ever want to go out.