Calapan, the capital of Mindoro Island, is nothing more than a convenient place to break a long overland/sea trip from Manila to Boracay, in case you choose not to fly. We arrived at Calapan from Puerto Galera. It took two hours by jeepney and of course we had to sit on the roof. The trip was quite scenic though and the road not too bad. Alternatively, there are ferries and speedboats running between Calapan and Batangas on Luzon Island.
We have to admit that we did not explore Calapan thoroughly, as it seems to be just another small, dusty, chaotic Filipino town. We got a room at Calapan Bay Hotel near the port, which we were thrilled about. For 1100 pesos we got a bright, clean, air-conditioned room with satellite TV and bathroom with hot water, which was a real treat after spending a few weeks in the Cordillera. We had a dinner at the hotel's restaurant, sitting on the terrace by the seaside, sipping a cold beer and enjoying the sunset. The food was nothing to write home about (we tried Korean BBQ style pork, but it didn't taste any different than any typical Filipino dish), however, Calapan Bay Hotel was certainly a great place to relax.
If you are on the way from Manila to Boracay, we recommend a 1-night stop in Calapan or, more precisely, at Calapan Bay Hotel, if you wish to relax before continuing the journey. Other than that, Calapan is not the place you would want to linger at longer than absolutely necessary.