We stayed at Paz de Luna B&B and Cafe. The place it nice, offers a decent breakfast and the rooms are comfortable and clean. The only downside (maybe for some people) would be the shared bathroom with the room next door.
Granada - Managua (UCA)
Buses leave from Calle Vega, Granada. We did not even reach the street and a mini bus was passing by the main square yelling UCA, UCA :) so we stopped them and jumped in the bus.
As far as we've been told there are buses leaving constantly between 6 AM and 6 PM so whenever you are ready visiting the city head towards the bus stop and take the first one. I read somewhere online that it is best to avoid the chicken buses as they take longer.
The price is about 1$ and the time 1-1.5h depending on how many times they stop.
Coming from Ometepe we took a taxi in the port of San Jorge, Rivas to Granada for 10$ per person. Price was negotiated from 20$ per person if I am not mistaken.
There is a bus to Granada from Rivas but the time from San Jorge to Rivas and then the bus trip was not worth in our case. I guess the bus should be very cheap not sure. For the schedules you can check this website.
In certain days of the week you can take a boat directly from Ometepe to Granada. You can get the info on the official website; just scroll down.