Well if you are going to park it and not move it ask the campground if you need to register it.
But: A general rule if you plan on moving it is to register in the same state as the one on your Operators License (The proper name of a "Driver's License" If you live in Maine, register in Maine.
A few years back there were a bunch of folks registering LLC's in a low low low tax state. their home states.... Got upset. and when the Treasury agent comes knocking and says "you owe us money" they tend to be very...er.. Liberal.. as to how much you owe (Meaning they estimate on the high side. way high) .
Home was where I park it. but alas the.
2005 Damon Intruder 377 Alas declared a total loss
after a semi "nicked" it. Still have the radios
Kenwood TS-2000, ICOM ID-5100, ID-51A+2, ID-880 REF030C most times