Made some more progress yesterday. I wanted to add an upper bout switch, so I bought a switch cover to measure for fit. I made templates with a hole saw for the inner cavity and the recess for the cover.
I used a forstener bit on the drill to remove most of the material. I then used the template to rout the inner cavity. I used a 1/2" template bit from Sears that removes about an inch at a time. It needed another pass to go deeper using the existing hole as the template. For the recess, I used a shorter 1/2" template bit from Stew Mac so it would be able to follow the template and only take off 1/8" or so.
Using my new $20 digital calipers (wow that is useful!) I found that the switch itself is 15/32". What a weird size. I had to go buy a drill bit for it. Then it was time to drill the wire channel. I used the long 1/4" drill bit at an angle toward the switch cavity, making sure to tape the bit to make sure I didn't go too far and using a piece of wood to make sure the top wasn't marred.
The NTune uses a pretty large connector, so I had to use a 5/8" long bit to widen the channel to fit it. Of course I forgot to tape it to show the depth so it went too far and chipped the wood near the switch cover a little. Not hard to fix during the finish, but annoying. Overall, I'm happy with how it came out.