There is sugar-free beef jerky, but I've only seen it available on the net... too late for that, I'm afraid. Just get the lowest carb jerky you can find. Usually the peppered or original are lower than teryaki or BBQ. Slim Jims are a pretty decent option, if you like those.
WalMart has a good brand of smoked almonds... though they're a little salty. Maybe not so hot if you won't have a lot to drink!

How about some macadamias? Nuts would be a great idea.
Make yourself some pepperoni chips... just put pepperoni slices in between layers of paper towels & microwave for a minute or two. They'll keep just fine without refrigeration, and will be something a little crunchy. I'd take cheese chips, too (microwave cut-up american cheese slices until browned... they crisp up & can be used as crackers), but I don't know if they'd affect you or not.
I'd make up some bran/flax muffins to take. They should be OK for a couple of days.
These are really good:
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Almond Thins
1 cup almond flour
1 packet of Splenda
1 egg white
pinch of salt, garlic powder, & onion powder
Preheat oven 325. Mix ingredients well. Place mixture onto a well greased piece of tin foil. Spray a piece of wax paper with cooking spray and lay over top of mixture. Use a rolling pin to roll out to a cracker thickness. Gently remove wax paper. Sprinkle more salt on top if desired and press lightly into dough. Score with knife or pizza cutter into squares. Lay tin foil on rack in oven. Bake until golden brown about 10 minutes. Makes around 50 crackers.
Carb count is about 13 for the whole batch. You can also vary the flavor-use ranch powder, ground bacon bits, season salt...
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Anything you can take in ziploc bags (that will then fold up small & take up less space!) would be great. If you want fruit, I'd go with Granny Smith apples... lower glycemic, and if you haven't been eating sugar, will actually taste sweet!
If you want protein bars, there are lots of low-carb recipes. Try a search in Yahoo/Google, or look at
www.lowcarbfriends.com.
5 people in a Geo, huh? Good luck!