We have been busy drying apple for storage & trail food. If you can core the apple you can hang it on a string line, or you can use a needle to do the same thing. You can also dry apple next to a fire.
We have been using our stove & heater.
A word of caution: Many years ago on a long trek I made the mistake of leaving my dried apple bag in my haversack with the flap closure down, but not buttoned. A possum stole it in the night. I found it not far away early next morning, but the bag although closed with a drawstring, was severely masticated!!! Yuck!