Catch a city bus on Av Lopez Mateos and ride to end of line. They are old school buses, painted white. I usually catch the "Central Camionera". The destination is painted on the front top of the bus. The cost is three pesos , and the driver only accepts pesos, and correct amount. Cheap way to see a city.
Bus stops are sometimes not marked clearly. When I get off, I usually do it where other Mexican's are getting off, and then get back on at the same location. Sometimes the bus stops have a small sign on a building, or streetlight. Other major bus stops have seating, just like American cities.
We went by car from Tucson about 2 hour drive. Good scenic road and places to visit on the way. Such as the MISSION SAINTE. XAVIER and the church. ' THE WHITE DOVE OF THE DESERT'
We walked around the downtown area and shopped. Clothing and booze very cheap.------------------------
Please visit travelogue up on the right top.
Walking is a popular way to cross the border! Nogales, AZ has many guarded parking lots close to the port-of-entry. What you will have to do is to follow I-19 to the end in Nogales and there you are! The cost of a day parking ticket is pretty reasonable. Most of the shopping and eating attractions are close to the border and within easy walking distance.