Hey there, those sound like some good ideas. Using a 5v regulator (7805 or whatever) will work just fine. The chip is rated to 5.5 volts but I'd just use a 5v regulator. We do have a "backwards batteries" protection diode (D1 on the bottom of the PCB) that you can safely skip if you make sure to put 5v in the right place (note that this will also bypass the main power switch, so that may or may not be a good thing for your application).
Good luck, let us know if you make something sweet!