With the exception of mountains, you pretty described Central Florida. Not sure if you have been here or not so I'll assume you haven't. Of course you have TONS of stuff to do. Disney/Epcot/Animal Kingdom/MGM/House Of Blues/etc, Universal/Adventure Island, Sea World, Wet N Wild, and International Drive which is pretty insane when you first see it. You also have clubs located in downtown Orlando plus clubs at Universal and Disney. Tampa is not too far also which also has clubs, Bucs games of course and the Gulf Of Mexico.
Depending on where you are in Central Florida, Daytona Beach is about 30-35 minutes away. Then there are TONS lakes and a few rivers. You also have Wekiva Springs State Park, Rock Springs State Park, Deleon Springs State Park if you wanna swim at a spring. All of those have trails to walk. Ocala National Forest is another place where some springs are but it's a little more north.
Cost is living is a lot less than other places from what I've read on here. You can get a pretty nice house for 150k and live comfortably on less money than other places. I haven't lived anywhere else so I can't really give a fair analysis of this.