Yup, the hardest thing about travel vlogging when camping is power. I use several powerbanks to charge my phone and batteries when off the bike. I tend to keep my phone charging when on the bike too. You can recharge the powerbanks from the bike on each ride, it won't necessarily keep up with your energy consumption, but it will slow it down and if they also can be solar charged, then when off bike, you can leave them in the sun to gain a little back too. I have a powerbank that can last me a long weekend away (4 days) easily when using a single camera and mobile phone, so if you both use as much power, you'll need to double up on them, or recharge them more often.
Try only using your camera on the interesting parts of the riding, highways are not generally very interesting, country back roads or mountain passes are, so save any talking you want to do for those bits if you plan on in helmet narration. This will save battery, make the footage more interesting, and also shorter, so your memory cards will last longer and you'll be able to make the videos shorter to keep them engaging
If you record stuff off camera, and are talking, try and include yourselves and the view/POI in the shot so the audience feels like you are chatting with them personally. Sometimes that isn't practical so mix it up a bit.
Oh, and viewers seem to love campfires and cooking your evening meals, so if doing that, record it!
The main tip is to have fun first, record second... if you spend too much time on making videos, you'll forget to have your own fun!
