Answer:
The subject of the sentence is We.
Yep, that's basically the whole task. To change the passage to become more 'upbeat', yet still share similar words to the previous words, the following could be changed to...
trudged= plodded
shuffled= staggered
scrutinised= questioned
sparse=meagre
closed in= confined
anxious= eager (Although eager and anxious generally do not share a similar definition, in this context they do as 'anxious' is used to describe being excited to do something, and share the same meaning of 'Very eager or concerned to do something or for something to happen'
pried= wrenched
confronted= suddenly exposed
puzzling=baffling
something=remarkable
used=castoff
questioned=pondered
anxious=uneasy
