From Literary Interest on Twitter, "A ‘dreamery’ is a place where a person dreams or is likely to dream. The first recorded instance (Blackwood's Magazine, 1826) suggests a hot bath as an ideal dreamery."
Again on Twitter, Claire King posted her ideal dreamery: "Under a blanket on a chaise longue, by a roaring fire, next to a large window, with the rain coming down outside on the wild green hills."
That might be mine, too, or if not hills, then a wild sea (as in Stanley Cursiter's "Rain" above).