One of the best walking tours in Alexandria is along the waterfront. Spanning from Oronoco Bay Park down to Waterfront Park, several gravel paths connect this 0.8 mile stroll. Stumble into Oronoco Bay Park on any given summer weekend and you're likely to find a festival going on, or a concert by the Alexandria Symphony Orchestra. The weekend after 4th of July, Alexandria celebrates its birthday with a giant cake and fireworks at the park. Make sure to keep an eye out for cyclists zipping down the Mt. Vernon Trail, which runs through the park.
Further south is Founders Park, a huge expanse of green right along the river. Grab a picnic basket and a blanket and spend a leisurely afternoon under one of the big shade trees. Or grab a group of friends for a game of volleyball in the sand pits. This is a great place for families, always full of kids running shoeless in the grass.
Wandering even further south brings you to the marina's wood boardwalk. Here the Cherry Blossom is docked, along with several other public and private boats. Sometimes vendors set up along the waterfront, giving it a bit of an shore-like atmosphere. I prefer to pass the vendors and continue down to Waterfront Park, where you can walk right on the water. The park is often dotted with locals playing with their dogs and enjoying a cool beverage.
This stroll is a great way to get some exercise in while visiting Alexandria and hang out with some locals.