DMV issues

Technically, you are homeless.

We ran into this years ago and they suggested putting down a family members address. Probably not 100% legitimate but no one really cares (do be up front with your insurance company though).

Mail forwarding services fall into the same category, you can't actually reside there but in some states, they don't really care to pursue it.

Here's what I have done to get around the PMB issues,
we use the Good Sam/PassPort America system in Crestview, so our address is:
5753 Hwy 85N
Suite xxxx
Crestview, FL 32536
By using Suite with your box number makes it good to go for most cases.

My friend had the same problem in TN. He finally just gave up and did it through FL.

A fulltimer that doesn't own property (land), can essentially choose any state as a residence. This is our 2nd time fulltiming and we remained AZ residents as we own a house in AZ that we rent out.
But the first time fulltiming, we chose South Dakota as our state of residence and went with a mail forwarding service there. Never had an issue with the SD DMV.

A mail service simply gives you a box, a Personal Mail Box, PMB. You couldn't reside in that PMB, so that address isn't a "real" residential address.

Some such as Escapees and St. Brendan's Isle can provide you a real address that you could live at, a domicile address. You would also become a legal resident of Texas or Florida for better or worse.

escapees.com

sbimailservice.com

The Escapees website has a section with info on domicile issues. I’d check here https://escapees.com/?s=Domicile

If in FL you can set up your legal domicile in Bushnell using the Escapees services.

Be up front with your auto/truck/RV insurance company.

Call the local DMV closest to where you lived in a stick and brick and explain the situation to a supervisor. She/he should be able to give you advice if you want to maintain same state for other reasons (insurance, license etc)

I used Good Sam Mail Service in Crestview FL.
No problems since 2015