A BLOOD-ORANGE SUN sank into the Adriatic on Croatia’s western edge as we reached the first hut on the Velebit Hiking Trail. Islands—the northern section of the country’s 1,185-isle archipelago—appeared in sharp silhouette as we took the last steps up to the ridge. For the next eight days, this 65-mile route would lead me and my two trekking companions south over rugged passes high above the shoreline and across the Velebit Range, the country’s largest and most challenging, to our final destination, the Dalmatian coast.
The...