As I'm not a mother-tongue speaker I'm still doubtful on the word choice.

As promised, I selected the sentences I'm not sure or. I really hope the .
1)The aristocracy is not present (is not represented, portrayed, described) in the tales.
2).They begin their journey (they set off?) at the Tabard Inn and go to Canterbury, which symbolizes the holy, celestial city of Jerusalem. The voyage turns into both a metaphor and an allegory for (of?) life.
3. She didn't respect the monastic rules that ordered to keep the forehead covered. (?)

1. represented

2. begin
3. that ordered HER to keep the (or her)

Sra