Not to throw cold water, but
Mark, I don't want to throw cold water on your project, but the BIG problem I had with my VHF on the headliner just aft of the compression post was constantly hitting my fat head on it. I could not approach the table without getting a new dent.As for the wiring, I pushed an electrician's "snake" (read springy wire) through the headliner to the access pannel above the head, where the compass wires are located. I then pulled the VHF antenna wire through the headliner. I did this when I moved the VHF to the outside of the head wall beside the companion way hatch. From here I can hear the radio much better in the cockpit.For my AM-FM-CD I am installing it in the forward wall of the head under the cabinet top. The controls are outside the head, in the cabin, next to the port seats. My speakers are located on the two stanchen access plates in the forward cabin, port and starboard and in the cockpit under the stern rail seats. The outside wires run inside the rails into the aft cubby area. Here is a picture of that wiring. With the speakers under the seats they stay well protected and provide good separation. I also didn't have to cut any big holes in the cockpit. Brigg