Many/most? states will not allow you use a mail forwarding service street address for drivers licenses, vehicle registration, and voting.
SD, TX and FL are full timer friendly states and most full timers choose one of them.
They do allow you to use a mail forwarding service street address as your legal domicile address.
I would be surprised if your state will allow you to use your son's college address for a legal domicile. You should check on that.
Clay (WA5NMR), Lee (Wife), Katie & Kelli (cats) Salli (dog).
Fixed domicile after 1 year of snowbirding and eleven years Full Timing in a 2004 Winnebago Sightseer 35N, Workhorse chassis, Honda Accord toad