I would vote with those who said "as a full time RVer, choose your state of residency according to all the info you can find, and register your RV in your state of residency"
As for those who try to register their RV in a state they do not reside in...
I tried to do that. I had a Montana LLC for several years for my internet business, and when I bought the new bus, I titled it in the name of the existing Montana LLC, and got Montana plates.
It took the Illinois revenuers less than a year to come after me, mostly because contrary to Illinois law, our Knight lived in Illinois for more than 30 days at a time.
I learned a lot while corresponding with the "revenuer"
I bought my RV in Florida. Before I hit the state line, they had told the state where I held a drivers license (Illinois)...
The Illinois revenuers knew everything. They knew where I stored the rig. They knew what RV forums I posted on, and what my user ID was on each of them.
In the end, I paid the 7.75% sales tax, plus some interest and penalties, Near $7000.
I'd suggest that fulltimers cross all the T's and dot all the I's in establishing residency in a tax friendly state.
Those of us not yet full time, it's probably not worth messing around.