Define "base". If that was where all the high command hung out and planned things, where Mon Mothma and Bail Organa and Leia and others were when they weren't on missions somewhere, I'd call that the base of operations. All the saboteurs and smugglers and such like the Ghost crew would be cells. Even if were a few dozen people operating in a city or on a planet or from a ship or three, I'd still call that a cell. Thousands of personnel and dozens of ships? That's a base. And we've really only seen one (at a time).
--Jonah
--Jonah