Two trails can be the same length and feel nothing alike. One follows a broad gravel path; the other climbs steadily over roots before dropping down wet stone steps. A mileage figure helps estimate the size of an outing, but it cannot tell you how the walking will feel or what might interrupt it.
Read the land manager's current description first. A personal trip report can add context, but its writer may have visited in another season, used different equipment or moved much faster than your group. An attractive photograph says very little about the approach to the place where it was taken.
Look for the shape of the day
Check whether the stated distance is one way, round trip or the entire loop. Look at elevation gain and the way it is distributed. A short, concentrated climb can be more demanding than a longer gradual rise. If the route begins with a descent, remember that the climb comes at the end, when people may be tired.
Notice terms such as exposed, unmaintained, scrambling or seasonal crossing. If a word describes an activity beyond your experience, ask the managing agency what it involves. Do not assume that every route labeled a trail is a walk suitable for everyone in the household.
Water crossings deserve particular attention. A description of a shallow crossing from last summer does not establish today's conditions. Check current alerts and be willing to choose another route rather than depending on a crossing that may not be usable.
Read the access information too
Trailhead parking, road closures, permits and opening hours can change the outing before you set foot on the trail. A seasonal road closure may turn a short hike into a much longer walk from a different parking area. Verify the starting point rather than trusting the first destination suggested by a navigation app.
Find the junctions and possible exit points on a map. Then compare the route with the slowest comfortable pace in your group, including children or people returning after time away from walking. Plan breaks where stopping is sensible, not just wherever a mileage target happens to fall.
Write a short route summary in your own words: where it starts, what the difficult section is and what would make you turn back. If you cannot explain those details, the description has not yet given you enough information. A simpler route with a clear plan is often a better choice than a famous one you only partly understand.