I have a little USB battery back up with a fold out solar panel. Just google “solar USB battery charger”, you’ll find a ton. I used it on a self supported ride and never ran out of battery. I would just bungie the open solar panel on my back rack in the morning and ride all day letting it charge.
I haven’t been since 2019, no way in the world I’m passing on the 50 Anniversary.
I have seen some ridonkulous prices before, but we always are looking for the VFW, American Legion, local restaurants, churches, or even just a slice of pizza at the Casey’s or Kum & Go; usually can find some decent prices at those places.