A word of caution....
After a long trip, towing a minivan on a Demco SS dolly, we pulled into a gas station. In order to line up with the pumps, it was necessary to make a very tight turn and I had not realized that the straps on the dolly had worked loose, probably due to the rain storm we had passed thru - we were newbies to the whole thing at the time
The following is what happens when the dolly turns and the minivan doesn't - the front wheel went over the front edge and after an hour of jacking, pushing, pulling and cursing, I gave in and called in the professionals (thanks Good Sam!)
Moral of the story - always check the straps and try and avoid really sharp turns.