Hi David,
The Tailgater is just a concept, no plans for it exist. I did post a grid of the profile, a few messages up. Beyond that, it's pretty much standard construction...
You could use solid plywood walls, see Steve Fredrick's page for how he did that.
Then you just attach a bunch of stringers and 1/8" plywood, inside and out.
I have a complete photo album of my construction, which is done the same way...
http://www.mikenchell.com/live/index-frame.html
Will that get you started?
Mike...
P.S. For the a/c, put it in the galley, right next to your laptop... my photo album details that too!

The quality is remembered long after the price is forgotten, so build your teardrop with the best materials...