Used 1.75mm Hatchbox Silver PLA; came out perfect. I doubt I needed as much infill -- maybe 10% at a minimum, but 20% feels like way overkill. Either way, I like it, and will be keeping it as its the first thing I printed (and successfully too)!
Will probably modify the design if I print the entire game set; it should have a horizontal slot on the track for the runner, so it doesn't bounce vertically when you try to launch the penny. Also not sure if Cura messed with the scale on me (possible I suppose), as us pennies don't quite fit in the slit -- dimes look like they'd work fine, but I've not one on hand to try (they usually get spent...).
Probably didn't need the brim either, being I have a heated bed. Decent model either way, very happy with how it came out!
EDIT: Same pictures on imgur, for higher resolution: