Elizabeth Brown, lead organizer of the workshop, makes the following recommendations.

The George Washington National Forest is half hour west of Harrisonburg, with the Monongahela National Forest further on in West Virginia.
Good guide: "Day and Overnight Hikes in West Virginia's Monongahela National Forest" by Johnny Molloy
Monongahela forest: http://www.fs.fed.us/r9/mnf/
George Washington forest: http://www.fs.fed.us/r8/gwj/

The Shenandoah National Forest is about forty minutes east of Harrisonburg. The Appalachian Trail runs through this; it is suitable for day hikes, overnight camping, or a scenic drive.
The park site: http://www.nps.gov/shen/
The Appalachian trail: http://www.nps.gov/appa/

For those not inclined to hike, the town of Staunton, thirty minutes south has a charming downtown, and cultural attractions that sound improving, but are also really fun:
The Black Friars playhouse, performing Shakespearean and other plays: http://www.americanshakespearecenter.com/
The Frontier Culture Museum, an outdoor museum about early European settlement of the Shenandoah valley. The museum is four farmhouses, shipped and reassembled from: Germany, Ireland, England and Virginia. Each is from the period of initial settlement, and all are run as working small farms. http://www.frontiermuseum.org/

Official Harrisonburg tourism site with links to bike tours, canoeing in the Shenandoah, and so forth: http://www.harrisonburgtourism.com/