Hi Lacey! I am also a Hill resident and was a bike commuter to Arlington for years. After trying a bunch of different ways to Arlington, here’s my favorite! Thankfully, between the nice bike lanes on the Hill, Madison/Jefferson Drives on the Mall, and the Mt. Vernon Trail, you can bike most of the way on lanes, and dedicated trails, with very little riding in mixed traffic. There’s a nice path from the Mt Vernon trail under the train tracks and the Parkway at Crystal City, and it puts you out right on Crystal Drive.
I prefer this way no matter where I am on the Hill, even if on the south side. It is do-able to go south from Seward Square towards the ballpark, across on I St, and out by the fish market and SW waterfront, but the traffic isn’t as calm. It is also do-able to cross on the Memorial Bridge,but I dislike the crossing of the GW Parkway and the crowds on the Mall, and it’s further out of your way for Crystal City.
Let me know if you ever want a ride guide!
http://tinyurl.com/3h3otvv