UPDATE: found a pipe scrap at the local ACE Hardware store which fit the tow coupler from Earthtools perfectly. Simple assembly and off I go. Unfortunately, I've found some problems. Clutch adjustment when I switch controls around is a real pain. Wide turning radius makes use in the orchard difficult. With any real load in the trailer, the BCS doesn't have enough traction to climb my hills. Have to split any loads and do two trips. Board for a seat was a lousy idea as I keep sliding around on turns and slopes. Really had hoped this would work, but need to rethink whole idea.
thanks for all the suggestions, input, links, ideas and etc. much appreciated !