A couple of things:
-If you haven't bought the TV yet, pay atten in to where the speakers are mounted. Some are downfiring (good), And others are rear firing (bad). If you end up with a rear firing set, be prepared for a sound bar as well.
-Unless on an articulated mount, it's not going to be easy to access the rear of the TV, so bring out everything you think you will ever need. I have 2 HDMI cables, a USB Extension cable, and component analog cables brought out and coiled in the cabinet. Bring AlL the HDMI jacks out since that's now the way the world rolls.. one never knows.
- Also think about extending HDMI to the rear TV. You may not think you need it now, but since you've torn into the rear of that space it might not be a bad time to install an active HDMI splitter and lace the cable out and on its way to the back