Doug,
I welded up the coupler extension today and bolted on the coupler. Do you think I should box the end of the lower tongue tube? I thought I could run the trailer wiring down the tubing but I'm wondering if it I should box it. I boxed the extension. Oh and here's a closeup of the welds. A little sloppy but I think I got good penetration.
I'm glad you posted the info about not going crazy with gussets. I hooked it up to the truck and bounced on the rear of the trailer, there's some flex but most of it was the truck bouncing up and down. I put the wheels on temporarily so I could pull it down the driveway and check for scraping. No problems there.
Next I need to weld the axle on for real, I just have a couple of goober welds on it now. I'll grind those off and redo them. Then its on to the outriggers...
Kerry,
My frame can beat up your frame
Bruce