Photo: Matt Winkelmeyer/Getty Images Jump to … April May June July August September and Beyond Trying to piece together an extensive summer-music itinerary? Or simply looking for an exciting option for one free weekend? Let us help. We’ve assembled a guide that includes more than 60 festivals and music events with details on who’s playing, when, where, and how to get tickets. We limited the list to mostly multiday U.S. engagements that feature high-profile performers, though there are a few