Because the expertly educational or the charitable service vacation has not become mainstream, traditional travel agencies may not offer much help in booking such a trip. One avenue to search is a college or university. Call the community relations or alumni office. Check headquarters at a favorite charity and ask if any seminar or work programs exist that would be suitable as a vacation. Explain what you're looking for.
Houses of worship are another possibility.
Many already offer spiritual retreats and camps and may appreciate offers of help or may know of service vacations. Penn State University offers learning adventures for individuals and families in all price ranges. You do not have to be an alumnus to take a trip. The Smithsonian Institution in Washington, D.C., has a panoply of educational trips geared to families or individual learners. Members, however, can take younger companions with them.