I think you have it right prouboy, or if it's for the 1st day you could pack in frozen meat and grill it on-site.  The veggies should last several days if not cut up.  Put 'em in tupperware and keep out of the heat.

What I like to do with tortillas is toast them over the fire.  Stuff 'em full, wrap 'em up like a burrito, toast to golden brown.  The tortilla stiffens up and you can stuff one in your pocket, walk around munching.