I've seen a lot of posts that seem to indicate an annual policy (comprehensive) running around $100. I pay about that through Progressive.
My coverage includes full replacement cost or cash payout of purchase price for the first 5 years, the replacement cost after 5. Comprehensive coverage and $2000 personal property coverage (no deductible) for theft.
In Ky, the trailer is covered by your tow vehicle policy when hitched up in the road, so if you have full coverage you are good while towing.
As others have said. Start by talking to you insurance company as the laws vary, as do how companies deal with RV's.
2011 FR Rockwood Premiere A126 Hard Side
TV=2011 Jeep Wrangler Sahara 2 Dr
Reese 66065 WDH, Curt WDH Shank #17120
Prodigy P2 Brake Controller, Mopar 7-pin Harness
B&M Transmission Cooler (#70268)