Estelí to Granada
Route: Estelí to La Concordia (via road to Miraflor Reserve), then Jinotega, Matagalpa, Reserva Cerro Apante, Susulí, San Dionisio, Escipúlas, San José del Remate, Teustepe, Malacatoya, Los Cocos, Granada.
Well graded dirt to La Concordia with a few rough rocky downhill bits (all driven by 4WDs), then pavement to Matagalpa. Ok graded dirt up out of Matagalpa round Reserva Apante with some more technical bits until the San Ramón-Susulí road. Well graded dirt from then until 15km short of Teustepe when new pavement started (presumably will be extended up towards San José in due course). Dirt/firm sand once off highway towards Malacatoya with a bit of pavement in the last few km along lake-front before Granada. We went through this immediately after rain and it was fine. River crossing between Malacatoya and Los Cocos runs all year
Granada to Los Chiles via Ometepe
Ferry from Granada to San Carlos leaves twice weekly (monday and thursday) at 2pm. You need to get there an hour or so early to buy a ticket for you and pay for the carriage of your bike. The part of the trip from Puerto Gracia (on Ometepe) to San Carlos is overnight, arriving at about 5.30am.
The riverboat from San Carlos to Los Chiles leaves from a different dock to the Ometepe ferry, and requires you to get your exit stamp from Nicaragua first (2USD fee). You then buy a boat ticket and hang around to board. Make sure you clarify the cost of carriage for your bike when you buy your ticket and before you get on the boat. Also make sure the boat crew give you a customs declaration form and an immigration form for Costa Rica during the trip. The immigration forms are the same as the form for leaving Nicaragua, so you could take two at the San Carlos end of the trip.