Late Latin tripalium, an instrument of torture (tres, three, plus palus, stake), gave Old French travailler, to torment, then to toil, then to journey, journeys being toil. English split the twins late: travail kept labor, travel kept the road, both into the 18th century interchangeably.
The folk memory the word preserves: medieval travel was lethal, pilgrims died by the thousand, and calling the road travail was not metaphor but statistics. Modern air travel's complaints are the echo of a word that meant rack.
Palus, the stake, also built pale (the fence, beyond the pale) and impale. The family trade is boundary and pierce: to travel is to cross the stakes of your own pale, which is either the romance or the warning, depending on the century.
When did the torture word become the brochure word, and what does that say about either?