I've used two pieces of angle, both have ends bent at an angle, for years. The angles have small drop pins (i.e. bolt) that corresponds with holes drilled in the bed. They just drop in. I move them depending on what I'm hauling. For the camper, they're set at 50" (camper is 49"). They're only about 5' long.
I use them for keeping the sleds on when the bed is used as a sled deck. Each one keeps the inner ski in location (sleds have about a 38" wide stance). When I don't want them at all, they just lift out.
Tie down is the easiest part. I use the short fast guns (Derringers) straight to the bed rails.
And storage... always need more room.
