Oh, you can do it. It's easy.
first check with YOUR DMV. tell them what your doing and they will tell you what you need. (I only needed
title, bill of sale, and form from the border) I wasn't required anything about a tag, but this is Oklahoma.
Second. go get the trailer. remember to carry ID's for everyone who goes with you.
heres another thread with border crossing stories.
nosy
I'm sure there are more. just try the search button in upper right corner.