Saga pearl ii, cabins to avoid because of noise?

We are planning a four week Crimean cruise on the Pearl ii in October 2014. We cruised on this ship in June when it was the Quest for Adventure. We had a satisfactory cabin forward on B deck but I noticed on the way to and from the main dining room that there was a good deal of engine noise and vibration around the aft stairs. The cabins where we were before are apparently all sold but we have been offered an outside cabin on A deck in the zone KK which is some way behind the aft stairs and below about the middle of the main dining room. Does anyone have experience of these cabins and whether they are subject to engine vibration and noise? We are typical elderly Saga types and light sleepers. The idea of four weeks of earplugs is a bit daunting. I should be very grateful for any information anyone can give