I use a Choo Choo Wagon. It can go up to 6 'cabooses' I think. Fantastic.

It goes smoothly and went somehwat okay in the snow this winter although I made the older ones walk. The kid snever complain about going in it and there is no fighting or kicking each other because each child is separate.

http://www.sears.ca/product/step-2-c...0704361-701700