I think you would not have a problem either way, either plate it or flat tow it and you can go in as dune ready.
Thing is though, if you do not street drive it anywhere else, why plate and insure it for just the dunes? I would probably flat tow it from the camp (dunes only) or plate it if you are planning some trail runs.
Hope to see you up there soon.
Hay, look at me... I have a signature.....