I leave a 5'ver down in Texas over the summer, covered storage is the only way to go. The rigs that are left to fend for themselves age three times as fast.
Be very careful on the advice you get from this forum. You're in Florida with high humid temps and salt air, most on this forum do not work under those constraints.
Shrink wrapping something in Florida I would think would be the kiss of death. When I was down in Florida I was taught to run the engine to temp once a month and shift thru the gears. Those that did not do that had seals go and leaks. An old neighbor had horror stories galore. Yet when I would leave my MH sit all winter in Northern MN it would start right up with no leaks or problems.
Your best bet is to ask local and not only the net. Go to the local RV shops and tell them what you'll be doing, they'll give you good advice for your area. Also pay attention to the forum members that are from your area, they will know a lot more then someone from the north when it comes to storing a rig in your conditions.