For a town its size there are relatively nice restaurants, generally within a few blocks on the south side of the square. Here's one:
California Cafe -- Carlisle PA -- 717-249-2028 The in town hotel
Comfort Suites - Carlisle, PA is in this area. The nearby old courthouse has several dents on it from Confederate cannonballs, each almost invisibly marked "July 1 1863". Many chain hotels on the outskirts by the I-81 and I-76 interchanges. Hotels will likely be pretty full during the car shows
Experience Carlisle Events. The Cars. The People. The Excitement. but not so much otherwise.
The main industry is trucking and associated monster warehouses (very prominent if you check Google Earth), leavened quite a bit by the small but high-end
Dickinson College , and the possibly more prominent
US Army War College where visitors are usually less welcome.
The area around North Street (a few blocks north of the square) has been the more challenging neighborhood but it won't really register on an urban scale of crime.
The U.S. Army Heritage and Education Center (USAHEC) has an interesting series of outdoor exhibits.
Boiling Springs, five miles out of the center of Carlisle, is a pretty little village with a small lake to walk around. The Appalachian Trail passes by the lake and has an office in town. Look behind the post office and behind the pool to extend your walking pleasure. Nearby Allenberry Playhouse is professional theatre offering a series of old standbys.
Search on here for much more info, including photo tours of this generally pleasant and well-kept community.