There is a huge difference between the way the insurance companies handle a RV as opposed to a Enclosed/car hauler type trailer. RV's a much simpler to insure because they have a none value. They come equipped from the factory with a certain trim level, and mostly anything else you would put into the trailer would be personal items like clothing, food and so forth. Enclosed trailers are very different, they may or may not haul the same thing every time they go out on the road. Their weight is also their fore most likely to be different as well. Many people, myself included, add additional options,parts,and tools after they take delivery of the trailer which can greatly affect it's worth and make it's value hard to asses. I have always insured by trailers (one stolen) threw my present carrier, Allstate. My agent has gotten use to it now, but he had never written a policy before I came along. I can not imagine being on the road and not having the trailer insured it would just be too big of a risk. They don't seem to mind writing a policy for liability and comprehensive insurance, but they will not write one for the contents. They refere to contents as meaning, anything that is not bolted or permanently fastened to the trailer. I added quite a bit to my trailer after I took it's delivery, and most of that will be covered. But anything like cars, jeeps, ATV's, parts, tools will not be covered. And most cars and trucks have an exclusion in their coverage that does not cover them when transported, so check it out. When we were running show cars and race cars, I checked into insuring them, but it was just to expensive to do. Most want a 5th to a 4th of the value to cover them, that just makes it too high for most. There is alot of trailers stolen every year, it has gotten so bad, that it almost makes you think twice about taken your car and family on the road while hauling. I never liked that feeling of being un-secure and in strange territory. It is not hard to have 150,000-200,000 dollars going down the road while towing, it's like a huge billboard saying come and get me.