I agree with Paul re the Trailer Life Navigator CD - it's mediocre at best, either as a map software or campground guide. About the only thing is does reasonably well is to provide a list of campgrounds in the vicinity of a city or town. That's OK if you must go to a certain place and need to find a campground near by, but not very useful if you merely want to find something along your route of travel.
I returned my copy of the 2006 Navigator CD for a refund. Recommend the hardcopy Trailer Life directory instead.
Woodalls lists campgrounds that TL does not, and vice versa. There are enough differences that we find it useful to carry both guides and we purchase a new copy of each every other year, alternating so we always have the current year of one of them. I would estimate the overlap at about 80-85%. If I only carried one directory, it would be Trailer Life. However, Woodalls has better listings for smaller campgrounds and local public parks.
The other major directory is Wheelers, available in paper or CD. It is not as broad in coverage as TL or Woodalls and the information is not as comprehensive.
All of the above three are available online as well.