Carry the G Watch cradle in my rucksack. Get about 36-44 hours on a charge, so not enough to do a charge once every two days, but enough that you're probably going to get the hour or so near a socket to do it.

Edit: I don't use the voice features all the time (you do feel like a bit of a berk unless you're on your own), and I don't get hundreds of phonecalls and texts setting off the vibrate.