"Up" refers to a position that is above a given reference point (e.g., the ground floor). "Here" refers to the place where the speaker is located. So, together, "up here" indicates that the speaker is saying that he is at a position that is above somewhere else (generally, the ground floor, the sea level, etc.). "It is a trudge up here" is something you would say when you mean "It is quite a laborious walk to get from where I started to this high position where I am now." Although not a word-for-word translation, it is something like "爬到这里这么高的地方好累哦“ in Chinese.

The writer means "this high altitude" or "to this location, up high."