I am trying to figure out a way to do a dolly on the cheap.
[Off-topic: You could make your own for next to nothing. I just Googled, "dolly kit wheels," and this cool set of bracketed wheels came up in Amazon--only $115. Just add plywood and PVC pipe! You could also use a really good tricycle (I'm not kidding), since laying track in public walkways is usually a problem.]