In visiting Amalfi the tour guide spoke of a museum some 20/25 minutes up a hill. We decided to go to the museum prior to having lunch/visiting the cathedral. The good news is that the journey only took about 15 minutes (maximum) and the museum was well worth a visit.
For 4 Euros per person a guide took a group of 5 of around the museum and explained the history of paper making and allowed one of our group to 'start making some paper' using the technique of several centuries ago.
The tour took about 15/20 minutes so in 45 minutes you can make the trip up the hill and visit the museum - this is well worth doing in addition to visiting the cathedral.