D.H.
Boy do I understand! I am a mom of four very active children. Some things I recommend are: having lots of fruit on hand at all times. Squeeze yogurts are awesome. If you put them in the freezer, they can eat them like a frozen treat OR you can put them in your insulated cooler and they stay fresh and cold all day. They won't be frozen anymore but they are a nice, cool healthy treat. I also recommend having water bottles in the freezer at all times. Again, they thaw as you go about your busy day and your kids will always have cold water to drink.
Let's see...what else? Well, you know that grocery stores carry bags of baby carrots....I recently found a bunch of single serve baby carrots, like 6 bags of them bound by the package wrapper. Those were awesome because we didn't have any waste. They have individual ranch tubs for dipping and/or Costco sells small tubs of hummus for dipping. You can use that for crackers, pretzels, veggies. Sabra brand is the only kind my kids will eat and I started buying it after an article in Parenting magazine recommended it above all other brands. It is wonderfully smooth and rich but not filled with funky flavors. We usually get plain or garlic (which has chunks of garlic right on top but is mildly flavored in the hummus).
Cheese sticks are great to have too. Get multi-grain tortilla chips or low-salt Lays (they are yummy and Lays doesn't have the bad preservatives most other chips have).
A friend also recommended this one to me: cook your hot dogs till they are nice and hot all the way through. Then put them on a bun and wrap in foil. Put the hot dogs in an insulated cooler and grab some ketchup packets. The hot dogs stay warm/fresh for a long time and even when they become room temp, the buns are still soft and wonderful. Top with ketchup as needed and voila...good to go.
If you are worried about nitrates that deli meats and hot dogs have, boar's head is a great brand of deli meat that doesn't have any of the bad stuff. Also, hebrew national are a great choice for hot dogs.
Lastly, tortilla wraps are cheap and you can buy them with Omega-3's (mission brand). Wrap the baked chicken left overs or turkey left overs and add cheese, whatever else your kids will eat and wrap them up like the hot dogs...all ready to eat when needed.
Good luck!