Riverside County and San Bernardino County to the north form this metro area. Like many such metro areas in the Southwest, it extends far into uninhabited desert areas, in this case east through the Mojave Desert to the Nevada/Arizona border. Larger than nine U.S. states, it is often referred to as the Inland Empire.
I agree with tchrist that the word doctor in doctor appointment is a noun (attributive noun I believe), although the definition of an attributive noun is a noun used as an adjective, so maybe it's just semantics at some point.
Making a passport appointment is easy when you know when you will be traveling and your intended destinations. Keep in mind that the demand for passports increases as summer approaches, and that new immigration requirements stipulate that people have passports for many trips that formerly did not require them.