When I worked at a summer camp, the best care package cookies came with a slice of bread in the bag. Something about the bread makes the cookies stay moist. (The bread is often no longer moist.)
Damage prevention is in the packaging. Put the cookies in a tin or a ziplock (with the bread), and make sure it is packed full so they don't have room to bang around. Then make sure the tin/bag is surrounded on all sides by soft but secure padding (packaging peanuts or whatever). The idea is to make sure it is secure - no wiggle room - and padded on all sides.
Have you ever moved a box of dishes? Essentially the same idea.