Most trails have an unimproved (usually dirt or grass) surface, though we also include trails based on old roadbeds that have not been maintained here. Some are only wide enough for walkers, but others might be wide enough to accommodate cyclists.
Trails can vary greatly in terms of the effort required - for example they are more likely to include steeper grades. You can read more about our model for evaluating effort and then how we describe and map it
Trails can also vary greatly in terms of width, grade, and obstacles.
Strategies for building your capacity (planning your outing, finding your comfort zone, establishing a routine, and then reviewing progress) are similar whether you are walking a path, hiking a trail, or cycling on a route.