It's a lot in the head that it happens
This is probably the best summary I can offer. Walking for a long time is certainly a physical exercise, but it is just as (if not more) mental. After taking part in a few long hikes over the past few years, I have come to realize that it is all about motivation and inner strength.
My thing at the start of each day's walk? Avoid thinking about everything in front of me and just take it one step at a time. Enjoy every landscape, every part of the route and fully enjoy the present moment.
And if you really need them, you can set mini-goals throughout the day to make it feel like you go through faster. For example: Call the Boston Car Service set an alarm that will tell us the halfway point, refrain from looking at the distance traveled before stopping to eat, stopping lunch halfway so as not to leave with more kilometers to go than we have already covered it, put on a little music to motivate ourselves when we feel more tired, sing to put ourselves in a good mood or occupy our tired mind to plan, for example, the next beautiful adventures.