This is a frequently asked question, and the answer is:
1. Only one insurance company directly issues quotes, and that is Avemco.
To get a quote from them, call them directly. In recent years they have been not competitive (expensive) for quotes on RVs, but they often send out a nice baseball cap.
2. All other companies will not quote you, an individual, directly. They expect you to go thru a "broker" (like an independent agent in car insurance). A single good broker should get you quotes from all the non-Avemco companies (there aren't that many). In fact some companies take a genuine dis-like at being asked for multiple quotes from multiple brokers for the same person. So I recommend just picking one. Remember the agent's job is to provide service to you, answer questions, suggest things, discuss experience requirements, dual required, etc. I, and many others here, use and are happy with the Gallagher Agency (they advertise on the side banners, here on VAF. Call, ask for Jenny or one of her assistants, have a nice, free talk. They don't give out baseball hats, but they do throw a nice party at Oshkosh!