This boat didn't come with a trailer or dolly of any kind. The seller helped me put it on a flatbed trailer, and I was able to roll it onto the floor of my garage to clean it up. Clearly it needed some kind of wheels to make launching and retrieval possible.

I used the plans available on this site: https://my2fish.wordpress.com/tag/sunfish-pvc-dolly/ to make a dolly out of 1.25" PVC pipe, and I roll it up onto the flatbed trailer for transport to a launch site.

So far it's worked pretty well. I've been rolling it off the trailer in a parking lot and then hand-rolling it down a launch ramp, which can be pretty long. The walk down is not so bad, but coming back up can be a bear. The dolly works great to launch into the water, but because it floats, getting back under the boat for retrieval can be a bit strange. I have to force it down into the water and hold it down while shoving it under the boat. I imagine this will get easier with practice.