Don't drink the water or you are liable to come down with Giardesis, a nasty form of diharea that you don't want, believe me! Filter the water.

You might pack granola or GORP for snacks. GORP is a mix of granola, trailmix, and whatever. Trailmix is a mixture of dried fruit and nuts. I like to add some plain peanut M&Ms to my GORP. This is food that you can snack on at any time that you have a hand free. It is tasty. It helps your regularity. It provided good energy. YOu might also consider beef jerky as a handy, not very perishable food. Make sure your outfitter/guide knows you are carrying this, as in some territory this might be good bear bait, only the bait is unfortuitously in your saddle bags!

Don't forget to carry at least one knife and a sharpener which you know how to sharpen your knife with. Take binoculars. Have a shoulder sling for your rifles. Somepeople say you should take your own scabbard to carry your rifle on your horse, one which can be securely closed at the opening end.

Have a good time.