I've done lots of hiking, also in the worst of conditions, carrying a variety of battery dependent cameras (and/or light meters). Never had any problem at all with the electronics and/or batteries.

Ask yourself if you really require a fully mechanical camera, as this severely limits your options.

I myself wear glasses too. The viewfinders of the Voigtlander Bessa rangefinder series have always made me happy. Dioptres are available, standard Nikon thread, reasonable prices.

Voigtlander lenses are affordable new (the Skopar 50/2.5 is a fine lens), otherwise a used Zeiss (ZM 50/2) may just be in range.

BTW, the Bessa RxM series do actually have mechanical shutters (the light meter takes two cheap and everlasting LR/SR44's, but you're always free to use sunny 16).

Canonets are great cameras if properly CLA'd, but the viewfinders are by far not as nice as the Voigtlanders'. For me, as a glasses wearer, this is a big thing.