We hiked in Arches in 2006. I remember the road in being very hilly and fairly busy towards the start, but getting less traffic the farther in you go, as people peel off for the various parking lots along the way. There was one big hairpin turn at the start of the road that I would be nervous about riding down with traffic leaving the park. Mid-week would definitely be the time to do it, if you're going to attempt it!
I am sure there are others who have been there more than my one time who could help more.
Emily
Emily
2011 Jamis Dakar XC "Toto" - Selle Italia Ldy Gel Flow
2007 Trek Pilot 5.0 WSD "Gloria" - Selle Italia Diva Gel Flow
2004 Bike Friday Petite Pocket Crusoe - Selle Italia Diva Gel Flow