Sounds like a great adventure.
Did you find this page:
https://atontheair.com/
Especially the summit list:
https://atontheair.com/summits/
For yaesu handhelds there is a USB charger so you can use your powerbank.
Slim-jim is a great choice. I did a multiday hike using only solar charging also on HF with a FT-817nd.
Learning CW will reduce weight even more. But I know that is not so easy.
73 Joe