Most people contemplating fulltime living in an RV are looking for a way to save money. Go to www.rv-dreams.com and look at their financials pages. They have been fulltiming for over 6 years and show their monthly expenses. This will give you something to work from to come up with a fairly accurate budget to use for your decision.
You really don't need to spend $80K on the truck and 5th wheel. You can get a nice 5th wheel and a truck for $40 to $60K. The truck will have plenty of power to get you out of Florida if needed. A nice F350 or 3500 Dodge/GM is what you will see on the highway towing the larger 5th wheels (35 ft Plus).
Just keep in mind after 7 years a $30K 5th wheel will be worth about $10 to $15K. They depreciate a lot when they get older than 5 years.