Kennedy Center is just great, wonderful that you live within reach of it. The National Symphony Orchestra of Washington perhaps didn't make history like Philadelphia, New York, Cleveland and Chicago did, but there are a lot of interesting and good recordings in their archives.
I believe that SEN status would give you access to the Deutsche Bahn lounges when travelling on a train booked as a flight number. That's what the guardian told me, anyway. Once I got in when I honestly think I shouldn't have got in.