Relatively flat and smooth trails that can be completed by almost anyone.
May have a few hills, steep sections, or multiple surface types. Most people should have little difficulty completing.
Dominantly natural surface trails with more difficult hills, exposed roots, or slipping hazards.
Typically single track, natural surface, narrow trails with many hills or steep sections, tight turns, exposed roots or slipping hazards or other obstacles such as stream crossings or rocky areas to traverse. May require specialized equipment or technical skills.