I took the trailer over to my son's welding shop yesterday. We found some pipe we could recycle from an old swing set, and cut the tubing into one-foot lengths to make stake pockets. He welded them to the side of the trailer.
Plenty big enough for 1" PVC pipe, and I may be able to go larger.
So, I brought it home and located a joint of 1/4 PVC to give me a visual idea. It looks like the concept is going to work, but I've got to fine-tune the length of the bow.
This looks like it's going to work fine. Some fine-tuning, some more head-scratching, and we'll move forward.