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.
Doctor is the first of two nouns in a nounânoun compound. You can tell this because you cannot say âa very doctor appointmentâ or âa doctorer/more doctor appointmentâ, which makes it clear that doctor is not used as an adjective here. Just because a noun happens to modify another noun does not it an adjective make.