When I visited this park with my kids, we went to the east unit. Both units are in the greater Tucson area, but both are a decent drive away from the center of town in different directions. So, I was glad to have a chance to see the other side. Although the visitor center is a bit nicer in the west, the east unit has a scenic cactus forest drive where you can easily get out and take a closer look. Both have plenty of saguaro (suh-Wah-ro) to see.