I just fit our
Trillium into the garage. I was going to build my own caster system, but then I found a pair of vehicle dolleys at Harbor Freight for $50 for the pair (1000lb capacity each). I screwed a couple of boards together to distribute the load over the frame and to give about 1/2 - 1 inch of clearance between the bracket on the
axle and the floor. This gave me about 2 inches of clearance between the top of the trailer and the garage door frame.
Although the trailer pushed into the garage nice and easy, it is important to note that you need to have some type of wheel on the tongue to move the trailer around since there is no "pivot" point at the wheels (which normally makes it easy to lift the tongue). I had a small floor jack that I used for this.
-Isaac