I recently read a newish fantasy book that, it turned out, was ONLY about the journey. Oh my, yes a few interesting things happened along the way but it wasn't clear to me as a reader at first that it would be 98% journey and nothing more. I was always waiting for the main characters to get somewhere with a spot of hope (journey was super depressing) but it never happened. Being a bit vague as don't want to be too harsh on the book. But to me that was a journey done wrong.
Now I'm writing my own WIP with a few journeys in and trying to get the balance right. The characters travel a long way over a few months so I had to give some sense of the journey and time passing. So I began a chapter where it was clear the journey had already begun/some ground had been covered. If you can show that time/journey continues between the chapters, I feel that can work a bit to giving a scale of the journey without having to show all of it.