I have previously used www.antennaweb.org
and have found that site pretty helpful. I like your link for ease of use and better mapping/graphics compared to antennaweb.
I usually try to "map" the direction of the transmitters when I know we'll be staying somewhere a few days. I almost always ask the campground host if they know the transmitter directions and I always receive a blank stare. If I've forgotten to map the directions beforehand I find my self walking around the campground to see where others have pointed their antennas.
It seems to me that all campgrounds should take few minutes to add the transmitter directions and distances to their quick reference brochures they hand out when you check-in at the office.