Cefalú is a fisherman's village of 18,000 habitants that still maintains a medieval charm.
Walking distance form the convent you kind find a stairway that leads you to the Lavatoio (the laundry) a site that dates back to the 9th Century where the locals use to do their laundry.
Another great place is Piazza Duomo, where you can chillax and people watch , have a caffé, and later wonder inside the Norman Cathedral to wonder at the magnificent byzantine mosaic portrait of Cristo Pantocrator, which so far is the most beautiful depiction of this image that I've seen.
Cefalú has a small museum that houses a Sicilian collection from the Baron Mandralisca. One of the most important pieces in the museum is a Portrait that has been attributed to Sicily's most famous Renaissance artist Antonello da Messina, called "Portrait of an Unknown Man". A nice little collection for a
3 euro admission.
If the weather is good you can hike up to La Rocca for some outstanding views, which unfortunately I can't vouch for because it rained a lot while I was there.