Driving around the western US has to be one of the great road trips anywhere on this planet. The roads are generally in good shape, they are fairly empty, and amenities though not obtrusive are never too far away. You feel remote but it's not like you're days from the next gas station as say in the Australian Outback. Obviously, it pays to be prepared. You should make sure your car is in good running order and have it checked before heading out on the open road. A rental should be fine but you can't always count on it. One good thing about camping is you are always carrying your gear with you which would come in handy if you got stuck. Water is one thing you should always have with you and plenty of it. Organ Pipe National Monument is about four hours southwest of Tuscon and though not a desolate area, it's not exactly a thriving one either. One good thing about the border control problem here is there are plenty of border police in case you get stuck! Getting around the Monument in winter can be done sans car, whether it be by bike or van tours available at the Visitor Center. Outside this Jan-March time frame, you'll need a car or be in great shape to cycle in the heat.
Take two or three hours to enjoy the 21 mile Ajo Mountain Drive. It is a one way loop road that passes through saguaro forests and winds its way to the foothills of the Ajo Mountains and through lovely passes. There are many pullouts along the way and several opportunities for hiking. The road is not paved, so the ride will be a little bumpy.
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