Flagstaff is a city in Arizona.
180 North towards Grand Canyon National Park
Take the route 5 bus from the downtown transfer center to the number 14 stop. Walk out onto the 180 (also known as Fort Valley Rd.) nearby the Shell gas station. There is plenty of shoulder to stand on, and potential rides can pull into the gas station parking lot without disturbing traffic. Fastest time to get a ride is early morning.
I-40 West towards Kingman, Las Vegas, Los Angeles
Walk West on Historic Route 66 until you are opposite the Woody Mountain Campground and RV park. From here it's easy to catch a long distance ride.
I-17 South towards Phoenix
89A South towards Sedona, Cottonwood, Prescott
Walk south on Beulah Blvd. until you pass a neighborhood called University Heights. At this point the road begins to turn into the 89A, and most of the traffic is heading at least as far as Sedona.
Accommodation and Sleep
Buffalo Park, with an expanse of forest and grasses, is a great place for stealth camping inside the city. There are plenty of forest roads surrounding Flagstaff that offer free and legal dispersed camping as well. Lake Mary is especially accessible.