A trailer will need it's own registration/insurance and tying down the toad wont be easy, especially in an enclosed trailer. The trailer will also have tongue weight as well as an empty weight that will need to be added to your cargo and tow capacity.
OTH, the toad will stay clean and undamaged from rocks and road debris inside an enclosed trailer. It also wont "wear" from rolling down the road.
I think most motorhomer's go with flat towing, easy on and off process when you need a car.
A new base plate is cheaper than a trailer.
2018 Ram 2500 Tradesman, CTD/CC/SB/4X4/Equalizer WDH
2019 Forest River Surveyor Legend 19BHLE