I’ve always preferred storing my supplies inside the vehicle, out of sight and out of the way. About a year ago a made a ballistic nylon storage bag for my Maxtrax and rigged up a webbing system to hold it on the ceiling of my GFC.
I drilled 4 half inch holes through the sleeping platform as shown in my diagram, spaced away from any edges enough to allow for the 3" area washers. The G-hooks allow for quick attach and detach as well as tensioning. The center piece of webbing is doubled up with multiple layers of elastic to keep everything under tension. The angles of the triangle rings make both ends come loose when one end is detached, this aids in easy removal of Maxtrax from either side of the truck without opening the other side. Velcro was added to the end of the pull straps after the G-hooks and to the center section to keep strap ends secured out of the way.
~8’ of 1" webbing
~2’ of 1" elastic strap
~1’ of sew on elastic
x4: 1/2"-20 button head bolts
x4: 1/2"-20 nylon nuts
x4: webbing anchor plate
x8: 3" area washers
x2: triangle rings (3/16" x 1 3/16”)
4’: adhesive rubber strip (so boards don’t chafe on ceiling)
Disclaimer: my setup requires a long bed style GFC with it’s longer permanent panel up front and I take no responsibility for you drilling holes in your camper. Some sewing required.