Any advice on scooter wheel chocks for enclosed cargo trailer? anyone with any experience?

Take a look at http://www.powersportrider.com/CGI-BIN/H...
Street - Index - Wheel Chocks
For a scooter, get the smallest one to accommodate the small wheels and not interfere with the fender. Mount it to the floor of your trailer along with a couple of "I hooks" (I don't know what they're called. Go to a hardware store. It's a circle with a bolt attached to it). A tie down strap (can get them in the same cataloge. ANCRE is best and simple to use) hooked to the "I hook" and the handle bar hand grip (with Ancra soft hooks) is adequate for you purpose.