I have the Summit Viper as well. I added a bow holder, and bought a "Game Plan Gear T.T.S Treestand Transport System." It's much better than the standard straps the climber comes with, puts more of the weight on your hips like a standard hiking pack does. The way I have the shoulder straps attached, it doesn't clank around while walking to my hunting spot. Before I had the new strap system, I would take a small bungee cord and strap it around the 2 top bars to keep them from moving while I was walking.
Filling the frame with spray foam sounds like a great idea!
Filling the frame with spray foam sounds like a great idea!