Wow! Talk about a pain in the rear for shooting out and about in nature. I'd do yourself a favor for future outings. F's are cheap. Pick up an F-2 rear standard and a multipurpose standard for the front so you can leave the big P standards at home on this sort of trip, and end up with a lightweight and compact F-1. Doing this makes the camera about 6 lbs. sans lens and board – about as much as a Technika. The usefulness of most of the P's benefits (i.e. precision and solidity) is all but lost out in nature anyhow, and they do nothing but add weight (and quite a bit of it).

How did it turn out in the end? What lens did you use?