Shobac is next to Hirtle's beach and Gaff's point trail. A bit further down the road is The Ovens, a natural park with hiking trails and caves that one can kayak into. There are several places to rent sea kayaks nearby.
Shobac is close to Lunenburg, a very cute old shipbuilding town that is now a UNESCO World Heritage Site. Lunenburg is small and picturesque. It has several good restaurants, a distillery that makes good rum, and various other tourist town stuff. The Fisheries Museum of the Atlantic is a fascinating place — cooler than it probably sounds.
The south shore of Nova Scotia is full of beautiful coastline, scenic drives, and old fishing towns.
Halifax is a nice, smallish city with a few good restaurants and very many bars and pubs. If you find yourself there for a night, try to see some local music.
Kejimkujik is one of Nova Scotia's two national parks. It's about a an hour and a half drive from Shobac. Probably the best thing to do here is to go canoeing or kayaking: there is a system of lakes and rivers that can be looped through over several days, with beautiful back-country camp sites along the way. (This stuff has to be booked in advance.) It also has some nice hiking trails and lake beaches.
If you'd like to do a multi-day road trip around Nova Scotia before or after the workshop, the best bet is to drive to Cape Breton Island, drive around the Cabot Trail, and visit the Cape Breton Highlands National Park. It is a very beautiful place. If you're heading for Cape Breton, ask Dan Harris for recommendations (he grew up there).