Iggy, I would mount small hooks on one side, attach some kind of corded rope with a loop end and mount another hook on the opposite opening and use a good grade bungee across cargo to tie down the chairs etc. If I don't go with the Rhino stuff this is probably what I'll do. Sorta same way I put the tire covers on my rig, rope around back side of tire, loop each end and a small bungee across outside of wheel.
Another concern I had are the infamous hydraulic hoses that are exposed in the pass through compartment. I plan on adding additional zip ties, perhaps alot, and may even wrap them in somthing so stowed chairs and such don't bang on them.
2011 Georgetown 330TS
RAV4 on MasterTow Dolly