The 2018 Lake Arrowhead Village free concert series begins on May 18th and goes till September 8th, and includes some pretty good acts that cover Led Zeppelin, The Beatles, Johnny Cash, ZZ Top, The Beach Boys, Pink Floyd, Van Halen, U2 and so on:
http://thelakearrowheadvillage.com/2018-concert-series/
Not as great as the old Swing Auditorium but a lot closer to the hot springs...only 25 minutes from the Bradford Ridge trailhead.
Free lawn chair seating is available on the grass and in standing areas the dance floor. This mountain ROCKS !