My first thought would be to mark these as "Private Roads". This way waze will not route anyone through these roads unless the destination entered in the app was actually on one of these roads. Another thought (one that I have not used or researched) would be mark them as "Dirt Roads". Hopefully, "more senior" editors will chime in.

Pizzaman is right - private roads are the way to go if it's a private location like a military base. Only mark roads that the travelling public is going to use though and not something that's special. For military, see https://wiki.waze.com/wiki/Military_installations. Generally speaking, Waze won't route a person onto a private road unless the destination is on or through that private road.

For remote roads like logging trails, I would think that some drivers might want to use Waze, assuming they have a cell signal at all. Those I would mark as Dirt Roads too.