Hi guys. Here's an update.
I made some brackets for the axle. I'll probably run 1/2" tube where the balsa strips are. The cut in the steel is so I could bend the ends of the V-shaped bracket toward the wheel. I'll then weld the "crack" and the other joint. The balsa also helped me bend the metal just enough to maintain wheel clearance.
I had to adapt the trailer axle to my bike axle. The bike axle is 11/16" ID. I found a tube that was 11/16" OD and 9/16" ID. But it wasn't long enough so I decided to run all-thread as the actual axle. The tube is just a reducer. I'm running two 9/16" OD x 7/16" ID bronze bushings inside the tube and then using a 7/16" all thread as the live axle.
Here is a pic showing an "exploded" view of how it all stacks together.
The nut will be replaced with a nylock nut. The bike's axle doesn't sit flush with the large axle nut, so the two zinc washers bring it flush and prevent any rubbing. The bronze washer will be drilled out to 7/16" and sit opposite the flange on the outside of the bushing. This will allow the threaded adapter (once cut down) to sit between the flange and the washer on top bushing.
This is an assembled view. Like I said, the nut will be a nylock, and the zinc washer is taking the place of the bronze washer that I need to drill out. The cut down threaded adapter will sit in this "channel". The bracket will be drilled and the threaded adapter will be welded in this hole. Both V-brackets will then be able to rotate freely on the bushings.