Does it have to be Florida? I would recommend Arizona, Colorado, Oregon, Washingon. For 3 reasons:
1. I like them. :-)
2. They all have large cities, but lots and lots of beautiful wilderness areas, as well as varied climates. Mountains, plaines, oceans in 2 of them.
3. The majority of the people in those states speak standard american english without any marked accent.
There are many other great states and cities, but I'm prejudiced to those areas.