The author was disappointed with Darchen because the high altitude caused serious health problems, he had a bad cold and sleepless nights, there were no pilgrims around, and the town looked dusty, partially ruined, and cluttered with heaps of rubble and refuse.
\[ \text{Disappointment at Darchen} = \text{Health issues} + \text{No pilgrims} + \text{Dirty, derelict surroundings} \] \[ \text{Health issues}: \text{high altitude} \rightarrow \text{bad cold, blocked nose, sleepless nights} \] \[ \text{Environment}: \text{dusty town} + \text{rubble} + \text{refuse} \Rightarrow \text{no charm or inspiration} \]
Thus, both his poor health and the dull, dirty environment made Darchen a great disappointment to the author.