Just bought the rest of the propane fittings for the propane holding area. This weekends goal will be to build the wall liner for the propane compartment. We plan on using aluminum to build the inner walls of the propane compartment. I will then seal the compartment so that if there is a leak it will not come into the camper. Next week I will order the door with vents.
Tell us or show us how you attached the TC to the frame of the truck. I've always thought that a flat bed is a waste of $ and space. Just have a subframe which is only as wide as the bottom of the TC and attach the boxes to the truck frame as you did. Good clean job. I approve!
Those tool boxes look like steel. How did you attach them to the truck frame?
I was having a lot of bob and sway with my camper, which is smaller and surely much lighter than yours. I picked up a set of Timbren springs. They have drastically reduced the mushy, swaying feel, and are completely maintenance free. They also don't affect the ride one iota when the truck isn't loaded. And I don't ever have to inflate or deflate them as a part of my loading or unloading ritual. I'm not saying they're better (I've personally never used airbags) but they are a definite option to consider. I picked mine up on craigslist for $100 and had them installed in a leisurely 1 hour.
Go to http://www.cumminsforum.com/forum/ and become a member if you aren't already. Search hitch and you'll be scared to pull a lawn trailer with that setup. The factory hitch is VERY marginal at best and with the extra leverage your hitch extension will place on it, it WILL NOT have long to live.