AnEv your comments are quite perceptive.
Yes, that back area has special considerations quite different from the front, not the least of which is the different support necessary due to the lack of truck bed support for the rear 6-8 inches and also the lesser amount of plywood wall due to openings and the constant in and out traffic of body weight plus folding step mount. There was an original angle iron bumper across this. I plan to build something similar, but with more size and support and less fasteners into just the rear 2x2 span board.
I guess I had lots of these thoughts in my head and was only asking about a preferred screw method of the two I was considering as a portion of the overall fastening support in these areas.
And I am very grateful to you all as your comments and skills have helped a lot in trying to think about a best way considering all of it together. That's quite a task I am finding. And it would really be easy to get bogged down in too many possibilities and give up the whole thing (that isn't going to happen btw).
This whole camper is an example of "spreading the load", built in flex, areas failing due to improper loads such as non-original designed tie-downs, and failure due to water intrusion.
Regarding "glued" joints, of course the reason that works well is because of spreading the load over the whole joint as opposed to the screw locations only. No doubt it is strongest albeit reducing flex. But - there are other ways, and no, glue wouldn't have been needed in the front wall as that joint was fine. The back few inches of the floor were rotted, so I replaced the whole floor. Same thing with many of the plywood walls.
Back utility areas and doorway cleats or steel angle brackets are a distinct possibility. And ticki2's thoughts on the overlapping sides is actually going to happen on the sub-box side walls. I'll explain why when we get to that part of the build. I've been thinking the cleats thing too back there, I am just so hesitant putting too much material removal into these plywood walls. I think the original engineers thought so too and why they used straps.
My intention has been to use several fastening methods in a same location, each using a minimal stress on the materials of that area, but with all together giving it that "share the load" feature. For example, the sheet metal siding itself is part of the camper's overall structural support.
There are probably no absolute correct answers here, and there are likely many excellent options and choices, and of course some that are "much better" than others.
It's fun huh?
