Best to ship in a 5 gallon plastic bucket you can use it to sit on use it to wash clothes and for many other uses.
Water purification filter.
Socks - high quality hiking socks for cold months, coolmax socks for warm months
you can put in things like auto-trader and free add magazines that will remind them of home.
lemonaid mix, good coffee, other drink mixes that mix with water to give it flavor.
foot care and hygiene products mole skin, neosporin, foot powder, toothpaste, nail clippers, nail file, Vaseline, car max, eye drops
sling shot ( they have plenty of rocks)
feminine products (we have girl soldiers too)
nalgene or stainless water bottle
gun grease, patches, bore snake 5.56
the type of cushion seat a turkey hunter might use to sit on the ground
two part epoxy, gorilla glue, knife sharpener,
Think about what you use every day and what you would use if you were camping walk through a good sporting goods store and look for things that are interesting. I found some "Misty-Mates" you put water in it pump it up and get a fine spray to cool down
Like this
this makes coffee on a fire