2X on including Canyonlands & Dead Horse Point State Park on your visit. The viewpoint at Dead Horse is a short walk from the parking lot. Canyonlands has a number of hiking opportunities available, but you could also just make the drive through the park, stopping at the various viewpoints. The major viewpoints for both could be done in a day.
As to Arches, I'd want to spend at least 3 or 4 days if you are going to do any hiking. There is lots to see from the road or short walks from the parking areas, but some of the arches require a bit of hiking. Delicate arch is well worth the hike, at least in the cooler times of the day...