So far I've been able to get about 8 experiments working.  

Lessons learned:

The wire jumper ends break fairly easily, especially when I "rip" them all out of the board (memories of 5th grade!).  This also often leaves the pin stuck in the female header.  Also, the typical Dupont wire jumper pins are a bit small for the female sockets - they are a bit loose and don't make reliable connections and pop out of the sockets easily.  I did this originally to keep the sharp pins off the board, but now the plan is to replace the female sockets on the board with male .025" header pins.  The female to female jumper wires are much more secure on the header pins and the typical header pins I use are pretty robust.  Plus, they won't break!

Maybe you think I'm overthinking this, but if this part of the board doesn't hold up, it will be very frustrating to the user!

As there are a few other changes I'll be making I'll spin up another rev on the PCB designs.  The speaker sounds tinny as it's so small, so I'll probably replace the Solar cell real estate with a larger speaker...