From the good folks at Coach-Net:
This Philly cheesesteak stuffs into a loaf of french bread that you can pull apart and gobble up. The foil packet is perfect as it allows the cheese, veggies and roast beef to all melt together providing the same delicious taste as an individually proportioned Philly.
To make things a bit easier, before heading to the campsite saute the onions and peppers and store in a container in the cooler until you need them. This will allow you to easily assemble these sandwiches for a quick, but hearty lunch.