1.0 very easy (flat and short distance)
1.5 easy (mostly flat, under 4 miles)
2.0 easy to moderate (gently rolling hills, up to 6 miles)
2.5 moderate due primarily to length (5+ miles on relatively flat land or gently rolling hills)
3.0 moderate due primarily to terrain (a lot of gently rolling hills or several medium hills)
3.5 moderate to strenuous (a lot of medium hills, generally 5+ miles)
4.0 strenuous (Steep hills will be involved)
5.0 very strenuous (Steep hills and distance greater than 8 miles)