Today I made a final decision on my door posts and the access panels. I drilled a 3 1/4 hole and then a 2 1/4 inch hole to make an access hole. See Image 1. I made the hole on both the left and right panels. Next, I spent some time cleaning, prepping and priming the access panels.
I also added some nylon grommets where the cable passes through the cross members. I believe I'll need to go back and epoxy them in place as an added measure of safety, as they are the pop in variety.
I then worked to trim the two overhead ribs for the slider assebly to fit.