Stan, the DRC didn't catch that missing trace, I was just rushing it to put it up. However I managed to screw some much bigger things up, so I'll have to fix all of them. 
I managed to swap the MP3 mounting connectors around, not a good thing, the sound board would not have had the right connections!
I didn't originally have that inverter, but that's an excellent idea. I started with the design of the MiniCommander interface, and it's using opto-isolators in place of those inverters. I didn't think to change when I got the HC14 in the mix.
I was thinking about the time constant being too short, that was one thing I was going to play with on the bench before going with the values I have. The little 10uf cap I have is a pretty cheap one, and as far as "going smaller", I have imposed a limit of how small I'll do SMT stuff. I know they can assemble it, but if I can't hand solder it easily, it's a big problem. All my resistors are now 805 size, and I keep the capacitors that large as well. I made the mistake of specifying a 201 sized resistor on a board, I couldn't even see the little things! I tried to solder it on for 20 minutes, and three or four ended up on the floor, lost forever! I can manage the 603 sized components, but I prefer the next size up for easy of handling.
For the receiver, I was going to make a tinfoil box for it and see if that helps. However, I figure if I can whack most of the EMI with the filter, that will make the receiver problem easier to deal with, and any shielding more effective.
The key to "pulling this off" is getting an MP3 solution that plays nice with the remote. So far, this one has had the other attributes that I was looking for.
Edit:
I corrected the graphics in the previous post, still a work in progress, but each step we get a little closer.
I'm not ordering boards yet, the boards are just to see how everything fits as I go.
