[sfont66]

Ok, first make sure your door gaps are as good as they can be. Then before any additional metal is cut out, test fit your new rocker. Some fit good , others need help, especially in the front door pillar area. Use sheet metal screws to hold the rocker in place while you work out the areas with fitment issues. Place the screws in areas that will be plug welded later, also make sure they are not in a spot that will eventually need to get cut out. By doing it this way you are able to tell that the problem areas or fitment issues are with the new rocker, and can sort them out before moving on to the other panels. This only works on trucks that don’t have extensive rust damage. Now that you know the rocker can again fit well the other panels can be addressed.
As far as a guide to cutting.... I like to save as much of the original sheet metal as possible, only cutting out the rust until you get back to good clean thick metal.
The area of the kick panel has multiple layers. Working from the inside of the cab back to the rocker, start with mocking up the inner rocker portion, then the kick panel, then the lower pillar patch, which will most likely just be able to slide over the rusty pillar, at this point the old pillar helps to locate the new patch, clamp it in place and dill out the 4 holes that go through the pillar patch and the inner rocker and floor support, this helps to locate the patch properly after the old rusty portion is cut out. Now reinstall the rocker and check your gaps again with door aligned properly. If good pull it all back apart and drill out your areas that need plug welds, sand spots getting welded to bare metal and apply weld through primer. Reassemble again, check door gaps, plug weld and tack a few areas so you can then remove door again for final weld and a ton or grinding.
This is obviously a simplified description of what you may have to do, but I hope it may help. Others may have more suggestions for you.
I may not explain things clearly at times, I do have some pics that may explain things better, but I don’t want to overstep on your thread. Also perhaps others have a better/faster/easier approach?