bay, i'm going to use your idea. I've got an old swing set frame & i'm going to make an a-frame tractor out of it. then I can use it for various chicken purposes.
Right now I have 7 SLW's about 2 months old in the "chicken condo", an old rabbit cage that I put legs on and enclosed the bottom, put a new roof on and still need to finish the "top floor". I will have to integrate them into the flock which will be the 2nd addition to them this year. This time I won't be able to close off the run to separate the new little chicks from the rest of the girls. I'll figure out something.
I like your idea of making a chicken tractor out of the old swing set. It is tall enough that you will be able to walk inside if you want to. If you are going to drag it around the yard, look at capping the bottom of the pipes (assuming it is metal) with PVC to make it easier to drag. And post pics!