I backpacked at least 10, 000 miles with the Sinar 4X5 monorail system. And I'm including a lot of steep high-altitude off-trail usage. The next 5000 miles or so are a little more difficult to recount, since I sometimes used the Sinar, but more and more started using a little Ebony 4X5 folder on long treks instead, as I got older. Now I frequently have a Sinar 4X5 Norma in my backpack for day hikes, or else an 8x10 Phillips folder, or even MF gear, but still rely mostly on my 4X5 Ebony for multi-day hikes. The Sinar is much faster to use, and more versatile, than any folder or technical camera like the Technika, which my brother used.
Any extended trip also necessarily includes all kinds of extra gear and supplies in the same pack - sleeping bag, tent, mountain-worthy clothing and gear, sufficient food and stove stuff, and in my younger years, a certain amount of climbing gear too. Since I prefer longer narrower perspectives, I keep an 18 inch cumulative rail on the Sinar, which is of course easily shortened if I need to shoot a wide angle lens instead. I use true external frame vintage US-made packs for all of this. Any official camera pack wouldn't begin to carry enough, or last very long either. Now the bigger question is, how much longer will I last before I wear out?