Current setup for overnight and two night trips is:
Novabeam battery (like the Anker lipstick but water resistant casing)
A multi-way USB lead (USB-A at one end with USB-mini, USB-micro, Apple 30pin and Apple iPhone 5 connectors at the other) means I can charge two or more devices at once.
Some rechargeable AA batteries
For longer trips I’d be looking at a dynamo hub with a converter like the Cycle2Charge and either a pass-through buffer battery like the Zendure linked to above or a simple USB battery that can be charged then used later to top up other devices.
The first method is low cost and basically works without having to think about it very much: charge battery at home; get to stop/camp; connect battery and device(s) and recharge.