Mike, I have used the Good Sam (was GMAC now National General) for about six or seven years now. Every year I go through the researching process to see if I can find better (cheaper) insurance. In every case, I've found insurance companies that will have cheaper rv insurance but when I add my autos (4 of them), it is more than my Good Sam....also I've found companies that have cheaper auto insurance but when I add my MH, it is more.
Since we spend 6 months in CA during the winter and 6 months in OR during the summer, one of the benefits that I've found with Good Sam is that I can reduce my premium in the summer by eliminating all auto insurance (with the exception of my toad) and in the winter by eliminating the insurance (with the exception of comprehensive) on the MH. This reduces my annual insurance cost by several hundred $$.
Hope this helps
Ron