I love Wolf Trap. Absolutely love seeing shows there. Parking is easy and not too far away, kids are welcome (though they do have to pay full price; ouch!), you can bring your own picnic dinner and wine to have on the nicely manicured lawn under the stars while great bands play, and the crowd is generally well-mannered. Best place to see a show during warm months.
Unfortunately, I fell asleep for part of Helm's set, so I missed the horn section stepping out in front and playing un-amped with only the pavilion's acoustics to carry the music to the lawn. It was apparently very cool. But something about the warm air and mellow vibe was so soothing I couldn't stay awake. That's not an entirely bad thing, coming from a chronic insomniac.