I wondered about this before, when your trailer is connected to the TV the auto insurance should cover it is my thought because if you hit someone with the trailer while towing it's the auto insurance.
"Well that didn't go as expected"
2015 Chev 2500HD Highcountry Duramax
Cedar Creek Silverback 33IK
Donald&Casey cairn terrier
Rest in Peace Mary my darling wife.
Scottish by birth Canadian by time.