Re: rocker panel replacement
Full replacement of the rockers is very difficult. You have to remove front fenders, pull interior parts along the bottom of the door, seats, carpets and the hard part, breaking open the rear quarters spot welded to the back of the rockers , then cut the rocker out and remove the lip that is spot welded to the floorboards and inner walls of the front and rear fenders.
If you have a couple holes in the visible area but the inners are clean and structurally is still strong but with holes in it, you have 2 options.
1) cut holes out and patch weld the holes. This takes a lot of patience, time and if you aren't used to it, luck. getting it lined up just right is important to match curves so be patient. You have to tack weld it in, then stitch weld it in keeping things cool so that you don't burn through the metal and so that you keep your sparks under control for the carpet and floor insulator protection. Fires and smoulering stink and can be bad if you aren't attentive.
2) Other option is chemical bonding. You cut the new rocker to the shape to fit over as much of the exposed area, a long piece that fits almost like a jigsaw puzzle.
then strip the whole old one as much as you can of paint along the outside edges for a good inch or more to make a full border of clean steel. Do the same on the inside of the replacement section.
Here is where you need 3M chemical bonding agent that is commonly used by bodyshops and avialable at NAPA. It's not popular with the old timers who favor welding but it's very strong, used commonly and much cheaper, faster and easier than welding. You smear it on both sides, stick 'em together and walk away, let it cure overnight. If you put a bit extra, you can even use it as a seam filler/sealer at the overlap and blend it in nicely. Sand all that down to shape, sealer/primer it, paint it. Done. Very easy.
Hardest part of this process is to cut the new replacement to the proper shape making sure not to block any of the drain holes in the rockers and if there are any that have closed up, open them up again. Be patient and take your time.
I can send you pics of completed chemical bonding appearance if you like. I've got the fenders off the car right now so you can see underneath after a couple years what it looks like. It's still clean and fresh and looks new.