RV'ing Florida in Summer

Insect repellent works fine to keep the bugs away. In the Keys there is usually a good breeze and the campgrounds have tree cover. So that makes it pleasant to sit outside in the evening. The theme parks will be hot and don't have much shade so walking around those (in Orlando) will not be pleasant.

The campground in the Everglades park does not have power and you will not be able to run your air conditioner. It will be hot, afternoon thunder storms are common though and will cool the air. But I would camp outside the park and make day trips into it.