Cheap energy sources for electronics during touring with low amount of sun energy?
Assuming you add the robust stand you were talking about here it should be possible to pedal the bike on the stand. Even pedalling gently will give you 50-100W of mechanical power that you can use to spin a small generator. I suggest looking for a dead RC toy and using the motor from that, since they often use that level of power. Ideally drive it from the chain rather than the tyre, but focus on making it work to start with. A little work on voltage conversion should give you enough power to charge the laptop fairly quickly, and with a little work you could even use it while pedalling.

Otherwise a hub dyno. A decent bottle dyno will not be much cheaper but will need more maintenance.