I finally got up the courage to try the speaker installation with the kickpanels in place. I did a little on-line research and found some pictures where the speakers are typically positioned. I laid out what I expected to be the center location of the speaker on my kickpanel and cut an undersized hole with a 2" hole saw. The 2" hole allowed me enough access to see what structure I had to deal with behind the kickpanel, but was small enough to allow me to adjust the center of the final hole as needed. I cut the final hole with a small cutting bit on a little battery router. It was actually very quick and easy.

I thought I'd post a couple pictures to try to show the location for someone else trying to tackle this.