Great recipe! Is there any reason why I couldn't cook the potatoes and assemble the packets at home, then bring them in our camping cooler for a w...

ChefOno is 100% correct. Potatoes, handled incorrectly, are breeding grounds for very nasty pathogens. Many believe that the culprit in "Potato Salad" food poisoning is the mayonnaise, but in actuality it is the potatoes. Rice, Potatoes, and many starches are behind many cases of illnesses, all remedied by rapid cool downs and proper temperature storage-usually the main culprits. Heres a specific post on Potatoes: http://blog.statefoodsafety.com/tag/food-poisoning-outbreaks/

So glad I asked--thanks for the quick response!

Good information, thank you.

Foil-wrapped potatoes and garlic are potential sources of botulism poisoning. The foil creates an anaerobic (oxygen-deprived) environment and, when combined with improper heating or cooling, enables c. botulinum to thrive.

You can read more about the danger here: http://www.fsis.usda.gov/FACTSheets/Clostridium_botulinum/index.asp