There are 9 train places within 25 miles of Ocala. Check the yellow pages for addresses when you arrive...or Google before you leave home.
Dan's Trains (Ocala) has excellent inventory but charges Walthers list with all new items. They have a lot of used stuff at good prices. All scales available. No layouts.
Trains of Ocala is OK and worth a look. O-HO-N. Display layout only.
PDK Trains (Ocala) is strictly mail order but owner does sell stuff locally sometimes. G-O-HO-N
Hobby Lobby (Ocala) carries basic O-HO-N stuff at list...occasional discounts. No layouts.
Rob's Hobby World (Ocala) has excellent prices and specializes in HO but carries N scale stuff. No layout. He will take an order and have it sent to you.
D&S Hobby (Citrus Springs-20 miles) HO & N. Limited inventory. No layouts.
All About Toy Trains (Crystal River area-25 miles) carries all scales. Several layouts. Decent prices. Does mostly mail order.
Noell's Hobbies (Wildwood-20) Limited inventory.
There's also one in Belleview which is a few miles south of Ocala but I can't remember their name. They carry HO & N at reasonable prices and have a display at the Market of Marion in Belleview.
The local train club (Ocala Model Railroaders) has awesome HO & N scale layouts. They're open on Saturdays, a few evenings during the week and welcome visitors. 352-401-0747