Bullfrog: When you say "brackets," I'm not sure what you mean. Without knowing what I plan to install at this point, I probably shouldn't ask you to elaborate, but would you? LOL.
I am currently thinking along the lines of a 30" wide vanity-type cabinet, possibly a student desk, and have even considered just setting up a folding table when stationary as needed. They idea of a hinged counter top attached to the wall in intriguing, too. I really only want a surface to heat a kettle of water or make a simple meal, since I cook outside and have a very effective set-up for that. I will want to incorporate a basic sink and gray water containment system.
My current set-up does include a sink with a five gallon water bottle and a 2-1/2 gallon gray water jug, but it is at knee level (space constraint), and has no real counter space. The new van will be 2' longer, which means the driver's seat can be raked back while leaving a tad more vertical space for a counter.
The walls of the new van will be lightly insulated and upholstered (an upfitted conversion/touring van). That will make it more challenging to find the ribs, but I believe detailed engineering diagrams are available for the base chassis, which should help. I've only seen videos of plus nuts being installed in existing holes in ribs, which will be harder still to find and, if I recall, must be drilled out a bit to accept the plus nut.
Might L-track be a good option? It seems securing at both the wall and floor would be best. Of course, any attachment is only as strong as the weakest element, so it might be overkill. 80/20 appeals in that regard. Pre-cut kits I've looked at are too wide (pricey, too).
There are also quick-release seat anchors in the floor, but I have not found those especially useful in my current van.
Carpet would not be my first choice for flooring, either, but I won't be removing it from the new van. (The carpet in my '96 has held up surprisingly well, but my "water works" is fully contained, and I don't cook in the van.)
Thanks to everyone for helping me think this through. This element is one of only a few hurdles I need to clear, but right now, it looks pretty tall.