In the morning I run at 10-11km/hr, and in the evening at 12km/hr and a bit faster the last 1km. Here in The Hague the pavements, the cycling paths are well lit in the night and cars really respect runners.
As for the higher mileage: I am feeling ok and rested, one month after the marathon. My evening runs replace the biking, so they are not very telling regarding my overall physical condition! I was thinking of introducing intervals once per week. We'll see!
Yesterday evening I ran 9.5km in 55min. This morning I ran 16.5km easy.