If you are new to reflector oven cooking, you should practice some before you take off on your trip.  Practice with amount of fire and fire distance in front of stove.  I once overcooked the brownies so that they had the consistency of jaw breakers and had to be blown out of the pan with dynamite.  ;D
You may have to turn the pan on occasion so the back or front will keep up with the rest of the pan in baking.  I use a pliers to grab the pan and a pan stiff enough when full (tin foil pans are too soft and "droop") to hold its shape when grabbed at one corner with pliers or pot grabber.  My reflector oven needs to be picked up and moved away from the fire to adjust the pan/goodies I am baking; then put back for more cooking time.  
PS-Cookies!  The cookie mixes available at the grocery store work great in the reflector oven.  You can make them as bars; a thin layer of dough spread into your cake pan.  Or you can make them as separate cookies which allows you to remove those which are cooked and put the rest back to cook a bit longer if needed.  There are also directions on the brownie or gingerbread box to make cookies out of the mix instead of bread/bars. 8-)