Hi DarkDuet, first of all congratulations for sharing your story and proposal idea.
I will be happy to help you developing the game for this special event.
I have developed a good variety of different 2d games and I can help you with yours, however I would like to discuss in private more details about how you want to implement the Geocaching mechanics.
Here you can see some of my old projects:
Some of my projects are available here on itch.io:
If you are interested let me know where I can reach you, otherwise you can get in contact with me through my website: https://biim.games
Thank you.