S&T isn't so much for finding campgrounds.
Yes, you do need a destination location, but I use customized POI files or some I've setup myself from recommendations, reviews, etc.
It is for route planning, which roads to take, how long the drive will be for each day (you can customize it so the route time works out to an average of 50 or 60 mph if you wish).
When I see S&T try to route me through I-35E in downtown Dallas, it is a simple click and drag to change the route. Other changes are useful.
I use S&T to setup a maximum drive time zone for a day's drive. That then tells me where to look on Allstays, RV Park Reviews and other sites for a campground near my target distance.
I strongly prefer to have everything about my trip on my computer. I've been caught with no cell service/ internet connection too often while traveling.
Once you get off the major interstates, there are gaps in coverage.
One thing I like about S&T is that it is very easy to review the planned drive for a day by looking at the details in the computer with my coffee before we pull out.
I can choose any level of zoom, to see the whole day, or to look at a particular intersection (sometimes S&T shows me something complicated, and I then go to Google Earth/Bing Maps - always check the date of the images to look for new construction.
I don't get to highway changes or intersections and not already know which way the turn will be. I've worked it out in advance.
Another thing is I keep an S&T file for each year's travels. Nice to look back and know exactly where we went, where we stayed, etc.
S&T has for me the best interface, the easiest to work with. Yes, the data is getting old, there have been some roadway changes. (Was recently on I-35 near New Braunfels/ San Marcos, TX - S&T has the revised exits wrong, so do current Garmin and Rand McNally GPS maps.)