I like the way you're starting out. Registration and insurance are often troublesome. It seems self converted motorhomes are unliked by the insurance companies.
People on this site are making quite safe conversions. That doesn't influence the insurance companies. There's been bad bus builds out there for years that are unsafe and it looks like the insurance companies are finally getting fed up with paying claims. You know how it is, it only takes a few bad ones to give us all a bad name.
Many of us, in the more difficult states, have registered as a van or other definitions of vehicles successfully getting insurance. Be flexible.