When I was conducting surveillance, I'd always look for foodstuffs that could be eaten without refrigeration. My mentors were a big help in this area.

The container I keep everything in is large enough for a pee canister for ladies (or children, if need be) : It's a 50 ounce Nestle creamer container (Sam's club carries them online.) It's got a plastic screwtop lid, has built-in grips and is a fair size for a vehicle kit. I keep everything contained in a larger plastic bag that I can use as a trash bag.

I use a Foodsaver for everything in airtight bags to help keep things fresh.

Pepperoni / salami sticks
Turkey Jerky
Beef Jerky
Triscuit crackers
Many varieties of nuts
Flavor packets for water (I've seen them for Crystal light, Kool-Aid, Mio, etc)
hot cocoa packets
single-serving cappuccino powder
Breadsticks
applesauce packets
vegetable chips (I use a dehydrator)
dried fruits
Fruit leather

peanut butter (sealed in a Ziploc)
nutella

Hard candies
mints
gum

That's all I can think of right now