I am a proud Geocacher. For some cache types (Mysteries) you have to solve a puzzle first, before you get the GPS coordinates for the final.

I use RTM to save the coordinates for all mysteries I solved, so that I have them at hand when I am out in the field.

Therefore I set up a new task in RTM. The name of the task is the name of the cache. In the notes section I copy the GPS coordinates. I also created a separate list called "Geocaching" where I file all these tasks. I do tag these tasks with "Reference" so that I can filter them out when using smartlists to get an overview for my todos.

Once I found the cache, I mark these tasks as completed.