What a tantalising thread. I have questions which may sound stupid, but one of these days I hope to pedal off into the wilderness away from mains electricity, but with a camera, small laptop, MP3 player, lights and phone. ...
The guage and only using a single battery is just a matter of appropriate electronics, although you may need to custom design some of this, which might be a bit of an issue if you don't do electronics.
A dynohub is likely to be the most efficient way of generating power. A bigish solar panel could be useful in a sunny clime (ie not the UK so much!), but I suspect would be better to put out when camping, since it'll be difficult to orientate most efficiently on a bicycle.
A wind turbine would only be sensible if you were cycling into strong wind. If there is no wind, converting movement into energy is most efficiently done with the dynohub, using your motion to produce wind, and in turn power a wind turbine and generator is guaranteed to be less efficient than a directly driven generator (ie dynohub).
Of course, powering or charging multiple devices could be a bit draining on your power sources. This will progressively become more realistic as devices become more efficient, although modern devices have already pushed things quite a lot in that direction.
Look up
Steve Roberts and his Nomadic Research Labs, for a guy who has been doing a lot of this sort of thing for over a couple of decades. I think he has changed from bikes (Behemoth) to a ship, since it proved impossible to carry everything he wanted to with a bike!