Noise from the Boardwalk is no worse than noise from a pool view and runs to about the same time - 10 or 11pm. Views including standard, courtyard/garden and leisure pool have always bee very quiet in my experience.
Yes, OKW will increase the chance for a really quiet location if you are sensitive to any noise at all.
Years ago when BW first opened, they held a street party on the boardwalk until 2AM with loud, pulsing dance music. I was one of those who complained and it went away after a year or so.
I beg to differ on the advice to go through EPCOT to get to MK.
Bus: wait 0-30 min, 15 min ride to MK. Total time 15-45 min typically.
Through EPCOT: Walk time 30 min, Wait for monorail 0-10 min, Monorail 15 min, second monorail 15 min, total time 60-70min