Hiking with weight will exercise all muscle groups except arms. Add weight to the pack/distance to your walk until you feel your are getting enough exercise. I carry a day pack with ~ 10 lbs of water (2 X 2 liter pop bottles) along with the normal day pack stuff.
Multiple ways to go for arms: physical labor (HDR), exercises without equipment (Van-Tramp), small portable exercise equipment (AGD). I usually get enough arm exercising with normal chores around camp. If not I have two: 1> weighted hiking sticks and arm weights on a hike, with aggressive arm movement, 2> full one gallon water jugs for curls, presses, extensions.
-- Spiff