Kaido
Elite Member & Kitchen Overlord
I agree. That is why I would not do a double wide trailer. They have amazing ISBU homes available now. There is one in Germany that is absolutely amazing. I was pursuing that path for three reasons:Safety, insulation, cost.
You may also want to check out systems like Quad-lock:
https://www.quadlock.com
I grew up near there and have friends who live right in your area. You'll want to keep in mind hurricane safety as well as humidity & flood issues. Blue Sky has a really nice off-grade moment frame system that would handle Florida really nicely:
http://blueskybuildingsystems.com/systems/frame/