There is a sweet run just north of FlagStaff. Go north and there is a big park a ways out of town, can't remember the name. You can park your car there. There is a trail called the Bright Angel Trail, ask around and you'll find it. You have to hike in a little bit but when you get down, you'll see a sweet river channeling through a pretty nice little canyon. Not sure what river that is but it's a fun run. You may want to bring plenty of bannanas as I believe it's an overnighter.