I've been trying to walk home from the train station. It does require some advance planning; Oscar has to give me a ride in the morning* and I have to make sure that my backpack isn't too heavy. (It's enough of a workout to lug my own 220 lb frame up these hills, much less adding another 30 lbs of library books.) This is not quite three miles, and there is a rather spectacular hill right near the beginning, but for the most part it's fairly flat and there are sidewalks. The downside to this is that I'm usually not interested in taking the dogs for a long walk when I get home.
On other days, I've been taking long walks through my neighborhood with the dogs. They enjoy it. While sidewalks are rather randomly distributed in my section of the 'hood, east of M street all the streets have sidewalks so it's a much more pleasant walk. I've mapped out paths of various distances, and I'm glad to find out that I can do a five mile walk while staying fairly close to home. Today I did 3.5 miles and I have to admit that I was starting to feel pretty tired near the end. The dogs went straight to the water dish and then collapsed on the living room floor and immediately fell asleep. :)
*Oh yes, I could walk to the train station in the morning, and I did do that once. It's definitely easier since it is all downhill and I definitely felt more alert and awake. But this would mean that I have to leave the house an hour earlier than I normally do and I have a hard enough time waking up as it is. The only reason I'd be able to do it is if I had no other option. Like Oscar being out of town with the car.