The grading of the walks is a little subjective, as an easy walk for one person could be purgatory for another. The grades below gives a general indication of the level of exertion required for each walk.
Length of walk
Grade 1 - A short walk (up to 4 miles)
Grade 2 - A medium walk (4 - 8 miles)
Grade 3 - A long walk (over 8 miles)
Type of walk
Grade A - Generally very flat
Grade B - Involves modest uphill walking
Grade C - Involves more rugged terrain and some steep climbs
For example, a walk graded 1-B indicates a walk of up to 4 miles that involves modest uphill walking.