As one of the most popular acts in classical music over the past 20 years, the Eroica Trio needs no introduction. But on this swing through California they’re not hitting the temples of art on Van Ness Avenue. This weekend, they’re in Santa Rosa with the Santa Rosa Symphony, playing Beethoven’s Triple Concerto. If that’s too far a drive, though, you can slip over to Mill Valley on Sunday, March 25, where the famous ladies will be performing at the Mt. Tamalpais United Methodist Church for the Mill Valley Chamber Music Society. This is a terrific way to see them up close in an informal setting. And since it’s a less-trafficked part of the Bay Area, you might still be able to pick up a ticket. But do it before you tell your friends.