At home: Remove cake mix from box and pour in freezer bag to prevent tears. Pour pie filling into lightweight container, or pack a can opener if necessary.
On the trail: Grease Dutch oven or line with foil for an easy cleanup. Pour pie filling into oven, top with dry cake mix and generously pour margarine over the top. Bake with hot coals for about 45 minutes. The cobbler is done when the top is golden brown and bubbly.
*You probably don't want to haul an actual Dutch oven for miles over mountains, so here's a simple DIY Dutch oven you can construct from just trail pans and small rocks.