I was wondering if someone could snap a pic of the underside of their cab in the rocker location. Just curious what they are supposed to look like. I take it they dont wrap around like a car.......at least I hope not.
Also I noticed a dent on the bed rail of my truck today that I never noticed b4, looks kinda like a ripple. Was worried that the box was twisting, but when shaking the sh*t out of it side to side, it seems fine....BUT the cab also moves but not in unison, is this normal? I know the cab and box are not connected, but they do sit on the same frame.
I've only ever owned 1 other truck and it did the same thing. Seemed like the box moved independently over bumps.....stiffer kind of

 

It is normal for the cab and bed to move independently of each other.

Here is a pic of my 96, that is a step that I installed a few years ago.

 

That was quick, so quick in fact that I went out and snapped a pic of mine.
Lets compare. I've always kinda looked past the rockers when looking under the truck bc at first glance I see a few holes but nothing that seemed major

 

well mine look dirtier and theres a few pin holes, but its there. The drivers side is missing the inner lip. I dont understand why they're built like this on a truck? There's a floor underneath them so why make a lip like that out for tin?
I was worried, bc if it was a car that little outter lip would round into the inner lip. But if you've ever seen a car where someone cut off the underside of the rocker panel this is what they end up looking like.
Honestly thinking I'm gonna go get a Mig welder so I can do all this stuff myself. Wherever theres minor holes in the floor and frame I'm platting the sh*t out of it, dont care what it looks like as long as it's strong

 

I think you'd be best off by stripping the whole area, cutting out everything compromised by rust in angular sections and replacing them with a plate of the same gauge as it's replacing. grind it flat, and put on fresh undercoating or the protective finish of your choice.

if you go in an "plate the sh*t out of it" (which I imagine to mean lay a heavier sheet over the damaged areas) you will end up with gaps between 2 layers of metal and will not be able to protect them sufficiently, which will cause it to rust out from in the inside very quicky.

 

I think I would simply remove the inner lip, bc its useless, and simply run a new piece of flatstock several inches wider and weld the whole seam.