Jennings and Moroso are the 2 closes tracks. Jennings offers open trackdays for anyone to come participate. moroso, Homestead, and Daytona, you need a race lisence to get on the track,
Sebring is not a motorcycle track, they do not have the run off required for motorcycles, meaning that if you rode off you wouldnt have anywhere to go, you would hit a wall.

there are other application tracks closer, motard/go-cart track in palmetto and Ocala,
motorcross track in Dade City and Lakeland