You're looking at greens,greens and more shades of greens...
I'm using Olive drab by Vallejo (and humbrol much earlier) for ammo boxes, go as straight from the can (dark) then clear gloss, then darken by washing with oils into the crevices, then gloss again, then clear flat ...and then lighten/fade with weathering process- I do it by pigments but you can do it with really thinned down "sand" tones.
However, for variation, go lighter for some (worn) by adding a drop of sand/khaki or brown, also add lots of scratches, stains.. Go darker for others (newer boxes) a tiny bit of smoke or dark grey..
Same Olive drab for tarps, duffels and general packs but you'd want to go a little more khaki or brown..by mixing a bit of the other paints.
Sleeping mats are a lighter green, somewhat hint of lime or blue (someone here knows the answer.
MOLLE or other camo packs, go stark colors if you're painting, if not use camo decals and lighten up by weathering.
Straps..be it on MOLLE, packs, or lashing types..there are a range of colors usually on the khaki side- lighter color than most gear.
Sleeping bags, go dark black grey, lighten the straps a bit.
Blend everything a little with yup "sand" color by diluted paint or pigments...same as you would the tank..
Hope this helps..and not too messy..230am here.
Follow the basic rules of colors and finish it with your style...to each his own..
See my AAV, Humvee,Stryker and M1 at my picasa album for more reference
https://picasaweb.google.com/114041413216204780388