I would not go with Good Sam/GMAC. I and others have had trouble with them raising rate for no apparent reason. After you have been with them, you can expect to get a BIG rate increase. When I received my renewal my rate went up over 60% with absolutely NO changes. Same coverage, excellent credit rating, no accidents or citations. They said that they 're-rated' my coach (what ever that means) which is why my rate went up. Others have had the same thing happen to them. Here's a link to the posting that I replied to a while ago. You should read the entire posting.
http://www.rv.net/forum/index.cfm/fuseaction/thread/tid/26598288/gotomsg/26598496.cfm#26598496