Insurance companies vary on what they will and won't cover. In my case the Ambo started life as a commercial vehicle. They do not care one little bit what you managed to get your state to register as, what it is in their eyes is all that counts. Mine started commercial and as far as they were concerned commercial it stayed unless I had a licensed or certified or some sort of " official" RV builder do the conversion.
Beyond that I had to state that there were no RV components in it. The underwriter rep went out of his way to drop enough hints so I could figure out what he had to hear officially. After that I was free to modify, just don't use the word camper or RV. Mobile office with convenience accessories. Job site command center with 24 hr facilities, blah blah blah. All in how you say it, much like how the garbage man is actually a Sanitation Engineer.
My insurance is still commercial, but the pricing was only dollars per month difference.