Chamonix 45n1 (2.7 pounds)
65mm f/8 Schneider Super-Angulon (0.6 pounds)
90mm f/6.8 Schneider Angulon (0.3 pounds)
150mm f/9 Schneider G-Claron (0.3 pounds)
Ultra-light carbon fiber tripod and small head (3 pounds)
Total weight: just shy of 7 pounds. But you'll need film holders. How many depends on what/how you shoot. But total you should be about 10-12 pounds total for a full kit with three lenses!!
I actually own all these lenses. So I went and tested this myself. It was a joy to carry such a small and lightweight kit. I ended up trading the 150mm G-Claron for a 135mm f/3.8 Xenar I wanted to try, but other than that I carried only the above, with 6 DDS holders and some extra Readyload color film.
I hiked for a few hours and made some nice photos. I occasionally missed having my nicer lenses but not much. The older lenses definitely were a little different than nice new modern lenses. The 90mm Angulon has a bit of spherical aberrations even stopped down but it makes the image have a subtle, but nice glow. The 65mm was hard to focus and the corners were certainly lacking. That 135mm Xenar ended up being not a very good lens. But otherwise, the lenses looked great. Really the only negative was some inconsistent shutter speeds. Most of these lenses have shutters that are 2-3 times older than I am so that's understandable. I can work around it (long exposures, or listening to the shutter speed and guessing roughly what speed it is shooting at and correcting the aperture accordingly).
I shot some T-Max 100 for black and white, and then either some old Kodak EPP in Readyload envelopes or Fuji T64II film with an 85B filter. Just wanted to see if the colors looked okay with some tweaking, using tungsten film with a corrective filter (they did).
Here's the images:
So there you have it. Some perfectly acceptable lenses for ultra-light-weight hiking. I even used some slight movements on some images (tilt) so they have plenty of coverage even. Most of these images were taken with the 90mm Angulon (I love the 90mm focal length).
Will I be selling my Nikon 90mm f/8? Heck no, but if I go on a trip and can't pack that kind of weight, I know that I'll be just fine with the Angulon, and other small lenses like that.