Colònia de Sant Jordi is the place you go to reach Cabrera. Two boat companies run the route (Excursions a Cabrera and Mar Cabrera), boats leave from the harbor, the crossing takes a bit less than an hour and in summer you should book your ticket online a few days ahead. If you only have three hours, take the fast option. If you want to actually see Cabrera, plan eight hours and take the full day with a swim stop in the Blue Cave.
The town itself has held up surprisingly well. The promenade is short, there are four beaches within walking distance from the harbor (Es Port, Es Dolç, Es Carbó, Es Roquetes, the last one is the quietest), and in November barely anyone is around. August is the opposite. I was there in October last time, perfect: 23 degrees, harbor full of boats but empty beaches.
What many people miss: the bunkers from the Spanish Civil War along the coast towards Es Carbó. Concrete chunks in the sand, half overgrown with pines. If history interests you, walk the coastal path from Es Port southward, the first bunkers show up after 20 minutes.
On food: the places at the harbor are touristy and expensive. One street further toward the village there are a few simple Spanish bars where locals eat tapas, ask at your hotel. Salt from the saltworks (Flor de Sal d'Es Trenc) is sold directly at the factory shop on the road towards Campos.
