You’re going to want AC. I live just north of Tampa and I just built a climate-controlled train room in my pole barn. Without AC, any exposed ferrous metal will rust; it’s just a question of how quickly. I’ve had track rust while sitting in boxes with desiccant before I built the new room. If you can get it, a second AC zone would be best. Trains are perfectly happy at 80 degrees as long as the air is dry. I used a ductless mini split just for my train room.
You’re going to love the Villages. They have about a half dozen model railway clubs, including O, and they put on two good swap meets and two layout shows each year. I always go to those shows. They’re some of the better ones in FL.
