Thanks to a creative posting I saw earlier, we made the decision to carry our bikes inside our TT, allowing me full use of the truck's empty bed for other things, like coolers, firewood and extra water.
Attached are two pictures of what I built from scratch, using parts from around the shop. Had to buy a few little fasteners of the right size, but each bike brace costs about 4 dollars. We found this to be the ideal solution. The two floor mats, placed upside down above our dining table, eased the notion of dirt/grease getting on the surface.
There would be minor adjustments made for any third set I would need, but only in the arrangement of a few washers and more wing nuts. The threaded bolt is a 12" stick of 3/8 inch bar, cut in half for the two bikes.
I also put a strap across the rear tires, securing the back halves together .
TT: Forest River Wildwood 2015.