Feb 25-27: Adults only at Contemporary (DH has convention there)
March 19-25: Spring Break at Tanque Verde Ranch and Arizona Biltmore on points
May 28-30: VWL
Nov 5-8: Food and Wine Festival, have reservations at VWL, hoping to change to either BWV or BCV at 7 month window for Epcot access.
Gopherit: Lots of great hotels right in downtown DC. JW Marriott and Hilton Garden Inn have great locations, in addition to Grand Hyatt recommended by another poster. I would not recommend the Mandarin Oriental. Is supposed to be a lovely hotel, but it is in kind of a weird location, and would be difficult to walk anywhere. Let me know if you have any other questions.