Tower Arch Professional Review and Guide
"The central paved corridor of the park, at times, can be quite congested. With a capable high-clearance four-wheel-drive vehicle, you have an opportunity to escape the crowds and visit far corners of a truly spectacular national park. The main features of this drive are Tower Arch, Marching Men, and Eye-of-the-Whale Arch. Although much of the drive is easy, there are several challenging rocky sections.
One of the hardest spots is at the beginning. You should have some backcountry driving experience and skid plates are recommended. Much of the drive is sandy so lower tire pressure if necessary to avoid getting stuck. Because of one steep sand hill, the National Park Service recommends travel as described here, north to south, only. Salt Valley Road can be impassable when wet. Route-finding is easy."