Flagstaff AZ has a new Hyatt Place, and is a fantastic trail running town. Flagstaff (7000ft) is much cooler in August than Sedona, which would be a great choice anytime but summer (though if you are willing to start very very early, Sedona would work in August). However, you would need a car in Flagstaff to get to the local trailheads. You can run trails that start at 7000ft or go to the Snowbowl ski resort and start at 9000ft. Excellent local trail running club with weekly runs if you want some company (true in Breckenridge CO as well).