single word for a challenging journey [closed]

Not journey or adventure.

Not crusade or expedition.

I'm not trying to insinuate purposeful / heroic.

I'm looking for a word relative to trial or crucible or calamity, but specific to a long and arduous journey.

Any ideas?

You could go straight to the classics and call it an odyssey - pretty much the defining work on long, arduous journeys.

Trek is also another good word to describe a long, and usually demanding, journey.

A a long and arduous journey reminds me of an ordeal.

• ordeal - (noun) a severe trial or experience, an experience that is very unpleasant or difficult. MW

Being trapped in an elevator was a harrowing ordeal...

• an extremely unpleasant experience, especially one that lasts for a long time. MD

They have suffered a terrible ordeal.

I think in this case, the word "Quest" fits pretty well. A quest often involves a difficult journey and trials to test one's strength and person.

You've already been offered trek, which is good - particularly in British English where it's frequently used with a bit of humorous understatement as a bit of a trek. If that isn't quite what you want, long hard slog is idiomatic.