I have found it very useful to be able to pull up a GMap that shows all the campgrounds, or nearby peaks along a highway. For example, in a trip to California, pull up a GMap that shows all the campgrounds.
The key to this are certain long thin areas along the highways. Typically a 20 km fringe on either side of the highway, and several hundred kilometers long.
As of 2020, a new GMap Form function has been added to the area page to allow these displays. Here is a list of such "highway areas"