I love hiking with my friends, and would like to spice the experience up beyond simply walking and enjoying the view. To make our 3-4-day hikes more interesting, I'm planning to hide a few caches along our trail beforehand containing stuff like beer, candy, and hints for the next cache.

To help my friends find the cache, I thought about giving them these challenges:
>Do a math problem to get the coordinates within ~100m accuracy
>Do an anagram where "A=1, B=2..." to get the accuracy within ~1m of the cache
>Do 10 burpees for a hint (can be used multiple times for several hints, and I will do the burpees with them)
>Put a rock in the first cache, explain that they will get additional reward if they bring the pet rock to a designated spot

What other challenges could I give them to make finding the caches more fun?

What are some other things I could put in the caches?

Suggestions for other stuff to do besides caches?

Do you play any games while hiking?