- Hang left. The Japanese drive on the left-side of the street, so, naturally they drift and hang on the left side of sidewalks/paths. You'll obviously figure this out fast as you collide with everyone as you run on the wrong, right-side for a few minutes.
- As with any big city, commuting hours are a nightmare to weave through pedestrian traffic, so run off-hours; you'll be up before the crack of dawn anyway.
- When you're crossing a street, look the opposite way you normally would (again, they drive on the left so everything's inverted).
- Even if the coast is clear, wait for the walking signal to turn green before you cross. Crossing streets out of order is severely frowned upon. Order reigns supreme and you'll be that jerk Westerner who disregards everyone else if you go with your instinct to just cross the street because there are no cars (yes, even at 5am when no-one but the guards/police are floating around).
- The Imperial Palace is a beautiful ~10k from Roppongi. Here's a recent Strava GPS trace of one of my runs around it. Lots of runners on this route; very popular.
- The Akasaka Palace is another gorgeous route. It's shorter (about half of Imperial), and includes a couple of hills. Not as popular as Imperial, but still a fair number of runners.