Cyrus,
I have posted previously about
Microsfot Live Map and I use it extensively when we are traveling. We do all of our trips by just traveling and when I get close to being tired, Earlene will fire up the laptop and/or the thick books, and start looking for a CG. If we know for sure that there is a specific area we want to stop at we will most likely make a reservation the day before, but we don't really like to plan that way unless it is a known nice area and we want to stay a few days. For just day hoping, we do it on the fly.
Edited: Oh! Once your fire up MS Live Map and zoom to an area, just type in the word "campground," or "RV Park," or "Camping," without the quotes in the live search box.
I use Microsoft Streets and Trips for a planning software, along with MS Maps. MS S&T will take you right to live search.