Nothing against roasted marshmallows but, if you're looking for flavor with the sweet, banana boats are a car camping delight.
Keyword car camping, dairy-free, egg-free, hypoallergenic, lactose-free, no dehydrator, no shellfish, no tree nuts, vegan, vegetarian
2Tbspdark chocolate chips
Tear off a 1-foot length of aluminum foil and line with a sheet of parchment paper.
Slice the belly of an unpeeled banana open, cutting about ¾ of the way through the banana, creating a cavity that you'll stuff with the other ingredients. Set the banana atop the parchment paper/aluminum foil sheets and wrap it up (with the aluminum foil on the outside, of course).
Place the wrapped banana over a grill on a campfire or near the coals, rotating as needed to ensure even cooking but always keeping the boat upright.
After around 10 minutes of cooking, remove the banana with tongs, let it cool for a couple of minutes, open the wrap and sprinkle the crushed graham cracker over the melty goodness thereby revealed.
Advise the campers that it'll be blazing hot and watch as they scoop out the banana boat and burn their tongues anyway.
There are enough possible variations on this theme that you can steer around most food allergies: