How walkable is the Lake neighborhood in San Francisco?

It depends how you define walkable. It is a fairly flat neighborhood so, if hills are an issue, this neighborhood is easy to walk. If you want to walk to restaurants, it is highly walkable. If you want to hike or go to the beach, it is highly walkable, too (depending which part of Lake you start from). If you want to walk to the post office, it is walkable. If you want to do all your shopping on foot (groceries), I am not sure how walkable...