I have attached a schematic, of sorts. 
The UNO (R3) inputs are to the right.
6 Exposed switches, and all the rest also are left.
I believe that this is switches MAXIMUS with respect to reserving USB/serial communications.
I know that there are a couple others inputs on the other chip 16U2, but I'm not going there. (At least not now) I don't even think there is a pad under some of these.
Anyone see problems with the schematic attached?
(any thoughts count...)
Thanks,
Richard
Inputs Side Schematic.PDF (212 KB)