[gumby79]

Slide mechanism... bucket seat slide rails look for a doner that has the seatbelts in the seat if stout /heavier is your goal, belts in floor if light weight becomes an issue. All 4 hard mounts can be rear of the pasanger this would cantaleaver the weight forward (heavier brackets ) I'm seeing~4" between the rear and mid pasanger grab mounts tie into theas . The forward point could interfere with passengers legs and an uncomfortable passenger is a squirrely passenger .
Looks like your your looking for suggestions beond the trip. Build your smallish aero box . Use the aero template for top and sides from your body+1"with a curved front to pickup the air and account for seasonal attire changes. The 3 sides will converge like a fish tail. Through in a difuser/fairing to clean up the rear finder body gap. Incorporate mounts for the bulky stuff tent fuel juggs. Could use riv-nuts to temporally attach the brackets. Sows some tent fabric and some fibreglass rods sowen in to make like an Armando or roly poly to fix aero of atachments. 9/10 of security is out of sight out of mind. If they cant see what you have then it didnt matter what kind of hardwere you use they were going to brake your stuff any how.

Dream Big Chisel Down To Reality