The Perch is on top of Capital One Hall and connected to the Watermark Hotel. Stop by the Starr Hill Biergarten to enjoy a beer or play a round of golf at Perch Putt -- a mini golf experience featuring food trucks and a Tiki Bar
The National Mall is ~15-20 minutes from the Watermark Hotel (could be longer depending on traffic). Make sure you wear comfortable shoes as it's a lot of walking! There are plenty of free museums (some require timed passes) along the Mall including the National Museum of Natural History and the National Gallery of Art.
2 blocks from the Watermark
There's lot of quick food options in the mall including Shake Shack, &pizza, mezeh, and Five Guys. The Galleria on the other side of the street also has options!