rv protections

Northeast Florida can get cold with temperatures well below freezing. For December, January and February you will need to winterize the RV to prevent freezing.

Mold is an issue in a sub-tropical climate. So is rust. I'd add a dehumidifier, or force the roof air to run by adding an electric heater.

My RV is in Orlando, Fl at the moment. Within one month the air compressor hose had mold on it.

moving from seattle to north east florida

Not sure reading your post where you are headed, but if its the Southwest, I agree with Drew about the UV damage. Along with the UV, things dry out badly in single digit humidity, like rubber seals and such. Then there is the dust that gets on and into everything. So keeping things dusted, washed, covered, etc is important. Mold and moss certainly not an issue.
On the other hand, if you are heading to the Southeast, while it is sunny and hot most of the year (think Florida), UV, leaks(frequent rains), mold and moss are an issue.
Just my 2 cents having spent time in both areas.

Check that your air conditioner works, and that the fridge is set up and operating well.

The only real maintenance difference I can think of is that UV damage will happen more quickly, so tire covers might be a good idea and expect plastics etc. to degrade a little faster and things to fade more. The batteries might need water a little bit oftener as well (if they're flooded batteries).

Congratulations! Sounds like it's about time for a change. I don't worry about anything.