Citydweller, 7 min + 18 min = 25 min vs. 14 min by car.
You have too much free time it seems. Why is your PO Box Downtown and not close to your home? I think that 1 hr to go check the mail it too much wasted time. What if a friend calls you for dinner or a drink?
What if it rains? Some cities in the world have covered sidewalks to facilitate pedestrial traffic during bad weather. Those cities also have all kinds of shops and interesting things to see as you walk. San Diego has nothing to see.
In New York, lower Manhattan is dead because of the huge blocks of office buildings. Upper Manhattan is much more pedestrian friendly and better place to live.