Found this absolute gem of a coffee shop right by Lake Chuzenji - TOKI COFFEE (or HOUSE TOKI) is one of those places that nails both the coffee and the atmosphere. The location couldn't be better for taking a breather during your lake explorations.
The place clearly knows what they're doing with their coffee, but what makes it special is how it feels like the perfect rest stop after temple-hopping or hiking around the lake. It's popular for good reason - seems like everyone who knows anything about coffee in the area ends up here.