We use Google Earth (GE) on a laptop for trip planning, and to scout out campgrounds and possible boondocking sites when on the road.
You can use GE's SEARCH function to search for "CAMPGROUNDS near CITY, STATE", and GE will list possible sites.* Then, click on the item in the provided list to zoom to that location and use STREET VIEW to see what the campground looks like. Between the satellite and street views, you can usually tell if this is somewhere you'd like to stay. Also, you can "drive" around on the streets near the site using STREET VIEW to get an idea of the route to the site once you get in the vicinity. This frequently helps by giving you a mental picture that's almost like having been there before, which makes the site easier to find when you get close.
This may or may not work with boondocking sites; because, by definition, these are usually off the beaten path, and it's less likely the GE photo car has been down these roads. However, I have often been surprised at the back roads on which those cars have driven.
The biggest problem boondocking with GE is the lack of a cellular/broadband signal. A GPS uses navigational satellite signals, so if you can see the open sky, your GPS will probably work. However, this is not the case with mobile broadband; if you are out of cell tower range, GE may be useless, or nearly so.
Our workaround for lack of a cell signal is to use the GPS to read the coordinates of our actual location, then plug that data into Microsoft Street & Trips to pinpoint our location on their map. Streets & Trips (and other similar software) is standalone and does not require a cell/mobile broadband signal.
As a backup for when your laptop/tablet/cell phone or GPS batteries go dead, make sure you take a compass and road atlas or other detailed maps. And, make sure to tell someone where you're headed before you lose your cell signal.
* Note: You can also use GE SEARCH to look for National or State Parks, museums, restaurants, hotels, hospitals, gas stations, etc.