I found out that my trailer liability is covered by my truck insurance, and that the trailer is not worth insuring on it's own for damage. But, just to be sure, I upped my liability limits-that doesn't apply to when I'm pulling the trailer, but I had already planned on paying a little more for insurance. Seems like a good use of a few bucks.
I've printed out a Texas from for Bill of Sale and something called a Travel Trailer or Park Model verification. Apparently things that are towed aren't really subject to a lot of regulations. I like this.