Reading a map for travel time, not distance
Thirty kilometres can be twenty minutes or two hours. Learning to read which is which is most of what separates a plan that holds from one that unravels by day three.
Distance is the least useful number on a travel map. What matters is the character of the road, the density of what is on it, and the time of day you intend to be on it. A mountain pass, a coastal single-track and a motorway of identical length are three completely different days.
Some quick tells. Roads that visibly switchback are slow and tiring even when empty. Roads that pass through a string of settlements are slow because of the settlements, not the road. Anything approaching a major city has a rush hour that is longer than you expect, and it is usually asymmetric — bad inbound in the morning, bad outbound in the evening.
Ferries, trains and internal flights invert the problem. There the constraint is not speed but frequency: a one-hour crossing that runs twice a day governs the entire shape of the surrounding two days.
The practical habit is to convert every leg into a half-day, a full day, or a nothing, and to plan in those units. Precision beyond that is false comfort, and planning without it is how people end up driving mountain roads after dark on the second night.
Basis for this note. Written from planning practice and publicly verifiable sources. Not a first-person trip report.
General planning method; not specific to one destination.