Sayre Kulp...first off: congrats on your goals keep it up! I was the fellow that posted on here back in August regarding the trailer adapter for our Sun EZ-3USX-HD trikes. I received my Booyah trailer Friday and Tuesday I will fabricate per your instructions on modifying the tow bar.
I realize you have no recourse being that you drive a sedan, but I did find a 6'x12' v-nose trailer to haul our trikes in. I checked in the rack by "Hitch-hiker, but it would have cost me almost $1000.00 just for the rack. I can get both trikes in the bed of my truck, but thy would still be out in the open and even if my tail gate locks, if someone wants the trikes, they WILL get them. I decided the trailer route was the best way to go. the trailer is enclosed so out of sight out of mind. The trikes stay dry and the Booyah trailer also fits in there. I do wish you luck in your search and don't stop seeking your goals and dreams.
Jerry