I think I've seen a few other threads where RV insurance was discussed extensively. You might want to do a search on the topic.
To answer your question I found Shelter insurance to be some good folks to work with and they wrote a policy for my Silverback with no hassle at all, and it weighs in the 13,000 lb range. Also they were less expensive than State Farm who has my home and other vehicles.
2016 Ford F-350 Lariat CC, 4x4 SRW. B&W turnover with extender. 2015 CC Silverback 29RE, fitted with Reese Goose Box. Amateur Extra Class K5TS, 2016 nights camped 16