Florida can get some nasty weather, even this time of year, To be on the safe side work on only being able to fly 2 out of 3 days.
Saying that, most nights are perfect, so if you don't mind doing a lot of night flying, you should be OK. I would allow a minimum of 4 weeks, 5 to be safer
You can do hour building without any visa's but if you require any training you will need one of those, along with TSA, Sevis, allow 3-4 weeks for that as well