If I'm traveling and enjoying it, I might be on a vacation, trip, adventure, or excursion.
But what if the journey is difficult, annoying, and altogether unpleasant? I'm thinking of trek, but that seems to imply difficult yet perhaps exciting. I'm looking for a word which represents the kind of travel that's a necessary but annoying chore.
For example, this might be used to describe a business trip which involves lots of boring meetings in a country where you can't stand the weather, or spending a day transferring between buses in order to meet a defense attorney.