As I've stated before on other threads. I've been taking a tally of success rate of people getting insured vs those having issues. The one common factor I see in all of them are:
The ones who get insurance easily:
1.) Has multiple items they are already paying insurance on. A.k.a, a home, 2 cars, or multiple buses, etc, then goes to insure a bus and have no issues with insuring it, even heavily customized. This helps greatly in them giving you trouble vs just accepting it without complaint. (I know many of you are using this as a home and sole item to pay insurance for, and this doesn't help you, but it is the truth.)
2.) It is Re-titled as an RV. This is important. A Bus is a commercial vehicle period in the legal sense, and on paper for the insurance companies. It's expected to be on the road far more and it's huge. If you can go to your local DMV and get re-titled to RV, Insurance companies are far more likely to give you insurance, and at a much cheaper rate. Because RV's are not driven as often as a commercial vehicle on the road. (it doesn't matter if you tell them you'll only drive it a few times a year if it's a commercial bus, but if it's an RV, it's on the road far less and on paper it looks far better and they are far more likely to insure it.)
3.) NEVER, and I mean NEVER volunteer information about what you are doing with it. Doesn't matter what you plan to do with it in real life, if they do not ask you the question, do not answer it, or volunteer it, and keep your answers concise and to the point, do not Embellish your responses. Answer only what is asked, and be honest. even if they ask you a question you think will ding you, if they get a hint you are hiding something that affects their decisions, so be calm but only answer what they ask for.
4.) Take an early picture of the bus pre-conversion. An early picture pre conversion makes the bus look safer to them, and they will ask for a picture for underwriting when considering insurance. Ask for a dollar value for liablility and full coverage, and they'll put that on their internal notes that it was already basically ready to set up for you. You can do this long before you get an official plan in place to get the process started.
The ones who do not get insurance easily:
1.) Do not have insurance period prior, were not insuring other cars, or a home, and want to live full time in a bus. ( This is the reality of the current state of insurers, sorry it just seems to be the case ).
2.) You volunteered more information than was asked for. You may accidentally say something that is going to make them worry. For example, a deck on the roof. When I went in for insurance, they didn't ask, and I didn't tell but I wholly plan on adding a deck on the roof, they didn't ask if I was going to have solar panels on the roof, so I didn't tell them. They did ask if I was going to have a bathroom, and I stated "I planned to go all out and have an enclosed water proof and water tight stand in shower with a full flushing toilet." I made it sound like it was going to get taken care of and not leak by using words like water tight and water proof so that they aren't worried about me asking insurance to fix it down the road, and I said it confidently which is important. They are trained listeners and listen to the inflection in your voice and often make decisions based on that inflection. If you sound unsure, they're going to be unsure in insuring you so say it in a way that will insure them. Remember they want as little liability as possible with you.
3.) People who did not go through the trouble of changing the title to an RV. Most states have to legally change if a request is made, but the process is not easy in most states. They require pictures, and receipts to show you put money into this to convert it. They won't go by pictures alone. They do ask for pictures, but you could of just taken pictures of a similar bus from someone else, they want to know you have committed to this becoming an RV before some states will change the title. If it's truly an RV they will change it, and this process can take a month in most states. As a bus it's a commercial vehicle, and some insurance companies will insure it while titled as a BUS if you state I wish to do "commercial vehicle for personal use". This is going to cost you more just as paying the government a commercial registration is going to cost you nearly 10 times more to register, insurance will cost more as well. So you have every incentive to work towards changing the title over to an RV. Insurance is cheaper than most cars on RV's because insurance companies are convinced they don't go out on the road nearly as often and so less liability that you will wreck it. (I realize some people live in their buses before fully converting it, and you will not be able to convert to an RV, and this is why it's difficult for you to get insurance, and why you should first work to full conversion, or enough to have a bed, kitchen, sink, and bathroom, and send pics with copies of receipts of purchases of materials for the RV conversion to the DMV to get that title changed to RV first before applying if you can. It's just reality.)
Other common stories I hear are, if you do a roof raise, or have a deck, or a bathroom in it, they won't insure it. My insurance at State farm didn't care that I had any of those things, and were fine with it.
You may say well maybe he just talked with the right guy at the right time. That may be true, however, as I've said, I've seen others with success and I always ask them if they had any other multi-line items already insured with the company. The answer has almost always been yes, they insured it without much issue.
I believe the reasons for this is due to the fact that you have to think of an insurance company as a Bank. They essentially are. If the Insurer has hooks in you already, or you have hooks in them by providing them previous prior business for years on other items, they want to keep that steady income stream and do not want you to leave to another insurer because they chose not to insure your Bus. So they usually give you no problems in these circumstances it seems.
Ultimately:
They see a Bus as a HUGE liability for them. It's huge, heavy, if you wreck into someone, you are very more than likely going to cause far more damage than you would if you were just in a car. Which equates to them forking out more money. A.k.a, chances are far greater due to the size and weight. If a Bus is the first thing you are trying to insure and they aren't making that money up from other line items you've been paying insurance for, they are less likely to take on that liability to keep you as a customer. This is what I've observed over time from people here and on other forums.