It may be slightly easier to get RV insurance if you have a fixed address, and you can legitimately avoid the question about "fulltime", though I doubt if it will be asked. Don't get hung up in details if there is a question about where the RV is kept - just give your current base location, e.g. where you receive mail.
As for a provider, you will need to shop around for coverages and rates. There are far too many personal variables for anyone else's choice to be useful to you. An independent agency that specializes in RVs may be helpful top you, e.g. Miller RV Insurance or Borden's. Also get some quotes from The Hartford (AARP Hartford if an AARP member), Progressive, Good Sam's Insurance (National General), etc.
http://www.millerrvinsurance.com/
https://bordenrvinsurance.com/
You need to think a bit about how much insurance and what kinds you need. Vehicle liability, collision and comprehensive, glass coverage, personal effects, personal liability, etc. You are insuring a house as well as as a vehicle, plus you have the risk of someone else getting injured or harmed in some way while in your rv or on your campsite. Vehicle liability insurance doesn't cover you if somebody falls down the entry steps while parked at a campsite.
