Go with the Buff for the base color, take Brown Sand (might need to lighten it) to make the color that's in between the lightest and darkest colors (in the Army we called this part of the camo "coffee stains"). Take Cavalry Brown for the stripes. Darken the Buff just a tad for the Desert Combat Boots. Lighten the colors if you are looking for a more faded "been there too long" look.
This is merely a suggestion. Good luck, looking forward to this project!