Volcán is what passes for an urban center on the west side of Barú. It’s really little more than a homely crossroads, but there are several sights and an entrance to Parque Nacional Volcán Barú  nearby. It also has the only banks and ATMs for many kilometers, as well as most of the dining options .
There are a couple of decent places to stay between Volcán and Bambito, but for the most part the choice is between lousy “budget” hotels that charge too much and overpriced “luxury” hotels that aren’t that luxurious. Unless you plan to explore the area extensively, you may want to head up toward Cerro Punta, 14 kilometers up the mountain, where the lodging and scenery are more attractive.
Buses between Cerro Punta  and David  all stop in Volcán (US$2.50) and Bambito (US$2.75). Look for the bus with “Cerro Punta” painted on the windshield. David-bound buses leave Cerro Punta 4:45 a.m.–6:45 p.m.; buses run every 15 minutes. Those coming from Costa Rica  can catch the Cerro Punta bus at Concepción rather than going all the way to the David bus terminal.
Taxi fare from David to Volcán is about US$25, a bit more to go farther up the mountain. Some of the highland hotels will arrange pickup at the airport or bus terminal, for a fee. Check with your hotel. Taxi fare from Volcán to Finca Hartmann is US$15, US$20 to Río Sereno.