If I could describe my idea of paradise, it would be identical to Isla de Ometepe - well, perhaps with a good spot to dance salsa thrown into the mix, but that is probably a rather unique request.
Set in the middle of Lake Nicaragua, Isla de Ometepe is an island formed of two volcanoes, Concepcion and Maderas with a strait running between them. How can I describe the island - it is lush, green, quiet, and while tourism is the main industry, it still has a rather 'untouched' feeling to it. The island itself is incredibly self-sustainable, with many organic fruit, vegetable and coffee plantations located throughout, and there is just enough infrastructure (roads in some parts, running water and electricity) to make it a comfortable enough stay.
Of the two sides, most visitors tend to stay near the Maderas side of Ometepe. We spent three nights at Finca Magdelena located at the base of Maderas, and then two nights in Santa Cruz. Many of the small towns heading east from Balgüe are nothing more than a collection of houses located within walking distance to each other and connected by a rocky path.
A bit of advice - if you are planning to bike around Maderas, be prepared for something that feels more like mountain biking, rather than a leisurely ride. It didn't look far on the map, but it took approximately 8 hours to ride around the base of the volcano - making few stops along the way, with the exception of one longer one, to fix a flat!
As for climbing the volcanoes, both can summited in a day. Maderas with a height of 1398 metres takes approximately eight hours to reach the top, and Concepción at 1800 metres takes between ten to twelve hours to summit and descend.
We climbed Maderas. For us, it was four hours to the top, including a small descent into the crater to visit the small lagoon within, and three and a half on the way down. The cloud forest towards the top was breathtaking, and while it was a tough and very muddy trek, it was well worth it the effort.
NOTE: When traveling in Nicaragua, Rivas is a common transfer point between the major towns including San Juan del Sur, Grenada and Isla de Ometepe. Pay extra attention to your belongings, particularly if you have your backpack on the roof of the bus - otherwise, you may find yourself suddenly packing very lightly.