I've done 2 hikes with a weighted backpack (25-30 lbs), and just today got an actual ruck sack from the military surplus store. My question is what would be the best thing to put in the ruck sack, and how heavy should it come out to? My best guess as of now would be books, coming out to 40-60 lbs, but I think that may be too much by some people's reactions, and probably a bad idea to use books. Any advice?