A friend of mine is a consultant to the State of Maine Afterschool programs. She just shared with me the fact Geocaching is being used in these programs. Also, she told me there were lesson plans and resources on a web site.
Perhaps this will help folks doing programs. I have not fully reviewed it but I am sure you can all do so and make your decisions on what to use or if it may help you. Here is the link: http://www.sedl.org/afterschool/toolkits/technology/pr_finding_solving.html