So I had the urge to get the Chillrend very early in the game. But when I came into that room, I decided to take Mercer's Plans as well. I think that messed up my game and now "The Pirsuit" quest does not exist anymore. I tried putting back the plans on the desk and re-copying Calcemo's notes but it wouldn't allow me to copy the notes again. By the way, I have a PS3.

The house is accessible before "The Pursuit"?

Bugs section?

This is a known issue. Don't believe there is any fix to it currently unless on PC.

Yeah, I did this thing where you jump on the barrel, then on the roof, then walk across this gate, walk up to the cieling, then drop down to the balcony.