South of Lake Havasu's Parker Dam, you'll find one of prettiest stretches of the lower Colorado River. Here, though there is plenty of development on both the Arizona and California shores, the river flows clear and free. The two units of Buckskin Mountain State Park are the best places to commune with the river and do a little hiking or bird watching. Birders will also want to explore the riparian areas of the Bill Williams National Wildlife Area, which lies just north of Parker Dam.
South of Parker, you pass through the town of Quartzsite, which each winter serves as home for thousands of RVers (snowbirds) who flock south from their homes in the frozen north. Quartzsite south to Yuma is just about the warmest place you can spend the winter and still be in the continental United States, and with its vast expanses of open desert, it is also just about the cheapest place to park an RV for a few months. With its numerous flea markets, gem-and-mineral shows, and roadside barbecue stands, the town has the feel of some vast refugee camp, but everyone seems to love the atmosphere.
While snowbirds think the winters in this area are heaven on earth, summers are more akin to hell on earth, which may be why the Yuma Territorial Prison was built here back in the 1870s. Today the prison is a state park and is one of Yuma's main attractions. Even before the prison was built, Yuma was playing an important role in the taming of the West. It was here that the U.S. Army in 1865 built a quartermaster depot for shipping supplies to its forts around Arizona. Yuma at that time was a river port, with paddlewheelers making the trip up the Colorado from the Gulf of California. Before leaving Yuma to head back to Phoenix, don't forget to drop by Lute's Casino, an immensely popular burger joint, bar, and checkers parlor in downtown Yuma. From Yuma, it is about a three-hour drive back to Phoenix.