Cab repair questions

[mike14_07]

My cab needs inner and outer rockers on both sides, i bought the outer floor panels to also fix a small amount of floor that'srusted through on the passenger side(i have both may just use the pass), pass. kick panel needs patched or replaced(probably just cut what i need off my patch panel), and small patches at the bottom in the corner of my rocker. nothings too awful bad, pretty normal rust from others ive seen. i have all the patch panels. do i need to brace the cab? i am just going to do one thing at a time. also i dont have doors yet and Ive seen them used for placement of the outer rocker. is this necessary? it looks like there is only one way for them to go on. im not worried about them them while doing the cab corners since i am not doing the full corner just a patch. or should i be? also the previous owner fill the gas cap hole, i would have any way, and did a good job, it just has a high spot now on the top. he may have hit it with a hammer to get it to fit right or warped idk, but can i simply heat shrink that spot? or? also any tips or how to's on replacing the metal i mentioned on my cab?