I'd fabricate a switch to go where the old heated windshield switch would go since you could wire it up from the back. Also check the mounting of the Speaker amp as on two of my cars it had fallen down and was stuffed back up in there.
Also, since it is Ryan, Add two more Cigarette lighter ports to the bottom of the dash (late 90'* to early 00 blazers had some nice units) and pre-run 2-6 CB antenna wires for him so he can pick up every frequency on the planet and a few that are not.
Pre-mount the Neon tubes under the dash
mount a washer nozzle in the leading edge of the HUD so that when he washed the window it sprays him
Add a Monster Tach sized boost gauge and a microphone so we can hear him giggle when he hits boost.
I think that'* all