I would not have travelled so far to lie shivering (22)
Travel here seems like a kind of quest. Epic. Maybe our speaker, feeling lost in his life, set out to figure some personal things out, and went on a journey toward self-discovery.
nor have watched the unctuous doctor hold up his needle (24)
This is kind of a creepy line. It's almost as if our speaker is being confronted by his own mortality. His sickness, and the doctor's presence, might be making him think about the meaning of his life more than he normally would.
I would not have seen through the cracked pane the darkening valley with its river sliding past the amber mountains (26-27)
Our speaker gazes out the window, contemplating the beauty of the world and his place in it. Nice.