I may have written this elsewhere, but I want to try to tell my experience.
And sorry for the long post! I'm loggoroic...
Many years ago I spent a year on an Antarctic station, completely isolated from the rest of the world with my colleagues, but working most of the time alone in an observatory.
Much like walking, my life consisted of sleep/eat/go to my lab/work/go back to my station room/eat/sleep. An occasional satellite call to my wife and child. For a year.
No money, no bills to pay, no cars, no house to clean, no trips to the grocery store, no shopping, no clothes to choose from. Every single day, for a full year. I had colleagues who helped me from a distance, people who cooked my food. I just had to do my job. I remember that experience as a dream, as a trip to another universe, even though I had spent many summers on the continent.
Of course, I prepared a lot for this year. I had enormous expectations and fears, but everything went very well. Friends and colleagues were enchanted by my experiences and stories.
Until the last day of my experience. Then I went back home. And that is where the difficulties began.
Because I was no longer the center of attention. Then-okay, you spent a year in Antarctica, but... who cares? move on! our lives went on, too. Now you are just like us!
And then I realized that I had prepared so much for this year, but ... I had never prepared a single step in the ground for the day I would return home to "civilization".
I have read similar reflections in many books written by astronauts: you prepare like crazy, for years, for your mission. The whole world follows you, you're the center of attention... but you don't give a single thought to the day when - literally, in this case - you're back on Earth, along with the others, and you're back at the back of the line.
Having said that, I think one thing you can do is this: try to think hard about the aftermath. Schedule other activities as if it were a pipeline, with many things in various stages of preparation, as they say "first in first out", and reject the (wrong) idea that life ends the day you finish your "camino", whatever that may be.