...if you click on the site name from the list of STARS systems freqs, it will bring up a map of where the site is located and the area it covers. Maybe this information has always been there but I just found it. Still not as good as the Google Map but it does show you a big orange circle of the area each site is supposed to cover. Also contains other information such as site location, Long/Lat, and range. Kind of cool.
Just a note that the circle is based solely on the range number, and nothing else. It's not based on area topography, antenna height, or anything else that can significantly affect the coverage area of an RF transmitter site.
Also, at the top of the site table, if you click the link that says
RR Locations, you'll be presented with a map of all the sites in the DB and their locations. Also not as nice as the real Google Maps map that has been made (since clicking on a site on the RR map only presents you with the site name, not the frequencies), but it's yet another alternative.