To fully experience the natural beauty of Moab, we recommend renting a car or an off-road vehicle. It will allow you to explore the national parks and trails at your own pace, and visit the more remote viewpoints and trails. Taxis and shuttles are available, but they can be expensive and limit your itinerary options.
If you have more time, consider extending your trip to Monument Valley or Zion National Park. If you have less time, consider removing a day and focusing on two national parks instead of three.