Where to stay: It has only few rooms to let and no hotels. Firoa Studios are the most decent ones: http://www.firoa-studios.gr/. In 5 years there will be many hotels to accommodate you. If you are camper you can camp everywhere on the island....
Where to swim: Everywhere, even at the harbour beach. Kedros beach is full of campers with the perfect beach bar-restaurant. Very cosy place and relaxing. Livadi beach is two beaches next to Kedros you need to walk 20-30 minutes down the cliff. It is for campers too and swimming suit is not necessary. No bar there so get water with you. Kalotaritissa at the north of the island, nice beach with a small taverna Mitsos to eat fava and mpifteki (specialties of the house)
Where to eat: Mitsos (Kalotaritissa), Tzi-tzi (Mirsini) - top taverna at the island, and couple of others at the harbour.
Any drinks?: Skatzohoiros is the place for coffee in the morning and drinks in the evening. There is also another one on the harbour beach.