Do you have any more pictures of that cap? I have the same one on an old dodge diesel and It’s great. I have mine insulated with a couple lights wired up but I’ve been trying to figure out how to get some windows in there. Your solution is pretty neat.
What does that leaf swap involve? I just added some helper springs to stiffen up the rear end on my 2002, wondering if that would help carry the load in the bed better.
I had the exact same demands and went with a pre-emissions cummins. Mine is a 2002, but anything from 1991-2006 (if cared for) will be reliable into the 500k mile figure and you'll have more space than you know what to do with. Don't have any pictures of the finished product handy but here's a...