One thing that always irritates the fuck out of me is when fantasy writers have absolutely no sense of scale.

I was listening to a book the other day where the story takes place in some valley, and the characters go visit a few towns that are weeks away from each other.

Reasonably fit people who are used to walking, such as anyone who lives in a place where cars aren't a thing, can easily cover 20 miles in a day. A three week journey on foot at that pace would be pretty much the same as walking from Chicago to Minneapolis.