Depending on where you live in Arlington, a car can be it's own hassle. I would think coming without a car and getting one if you find getting to the outdoors too difficult without and you have a plan on where to park.

Sweet Science is in my opinion the best coffee in Arlington. Their default coffee is the birdie blend from Rare Bird in Falls Church which is legitimately my favorite blend I've ever had. Free Wi-Fi, no time limit, friendly staff.