This poverty-stricken coastal village on the east coast of the peninsula was a trading port with El Salvador until the Contras blew it up in the 1980s. Authorities have yet to reestablish regular El Salvador–Nicaragua ferry service, but a new dock was being built in 2009, so it’s possible.
In the meantime, if you can find a local licensed captain you can make your own way to El Salvador, either to the port city of La Union or the tourist beach at Tamarindo, where you can find hotels, basic services, and buses to the capital. You’ll need to stop by the lonely immigration office at the end of a dirt path to get your passport stamped and pay the exit fee. The ride is less than an hour, there is no set fee.
On the road toward Potosí, at the tiny village of La Piscina, is an interesting community-based tourism effort called Ramsar Lodge (www.ramsarlodge.com [1]), located near a cemented-in hot springs and providing primitive wood-and-thatch huts with communal hangout area. Ramsar is for adventurous, open-minded backpackers who aren’t afraid to sweat or sign up to milk cows, make tortillas, and so on. For details, inquire at Vapues Tours in León [2].
A few more kilomters up the road, as you enter Potosí, look on your right for the very reasonable, locally owned Hotel Brisas del Golfo (tel. 505/2231-2238, $15) with five clean, private rooms with fan at a very reasonable price. Don Rafael Castro and his wife can prepare you three meals a day and help organize your volcano expedition.
If you’re on the peninsula in May, ask about the three-day festival on Meanguera, an El Salvadoran island that allegedly allows unchecked passport access during the fiesta. You can reach Potosí at the end of a three-hour bus ride from Chinandega [3]; about six buses leave daily and cost under $2 each way.
Links:
[1] http://www.ramsarlodge.com
[2] http://www.moon.com/destinations/nicaragua/northwest-coast/leon/recreation/guides-and-tour-operators
[3] http://www.moon.com/destinations/nicaragua/northwest-coast/chinandega