Ok kids, got my dirt wheels back on and took the trailer out for a good thrashing. Went down by the river to a spot I want to camp. Did a hill climb, deep ditch and log crossing. As you can see, the smaller rear wheel is not an issue. I think the fatter tire you get with a smaller wheel is a benefit as it won't pinch flat quite as easy. I can feel the trailer more with the dirt wheels on the bike but still no big deal. I went everywhere I wanted to go. In the video you can see some bouncing but not as bad as I thought it was. I should have loaded more weight in it. It really stabilizes with more weight. The shocks are just a shade too stiff offroad with a small load in it. It had maybe 15 pounds of stuff in it. I should have thrown a couple cinder blocks in it for the test. It will handle it no problem.
The video doesn't do the hill justice. It's meaner than it looks.