Well you got the answer, FL requires current plates. Since your trailer will be there year round you may qualify as a FL resident. If you spend 6 months in the state you're a FL resident. As a resident you don't have to pay the 13% tax on the site you're renting. At the campground we visit many of the people rent the site for 6 months, Adding a few months doesn't cost anymore because they save the 13% tax. This assumes they were already staying for the peak months, most expensive, and the extra months are not peak and a lot less expensive. Where we stay Feb is the most expensive and cost more than twice what some of the non-peak months go for.