Nice find! Yeah, a lot of use over the years. Years as a sailor's boarding house does not wear well on a place, I imagine! Interesting also nomenclature, "best chamber" misspelling or is that what they call it up there? We use Master Bedroom or something. Racist, no doubt.
I think the closest equivalent in modern usage would simply be room, since the bedchamber is labelled as such. Similar to chamber music, which was named in contrast to works requiring larger forces in a hall. Interesting that we have discarded the French-influenced chamber/
chambre (except in the sense of a judge's chamber) in favor of the Germanic-derived room, in a rare case of backwards evolution.
Also interesting that, in Norwegian at least,
rom (room) denotes space, hence the old word for an astronaut is a
romfartsmann, while a room in a house is a
stue, which survives in English as an old word for brothels, i. e. the stews.