Thanks, everyone for your kind responses! 

The Candlewick offices are new, having just made the horrendous move from Cambridge to Somerville MA.  In the old building, Candlewick was spread out over two floors but now they're housed in one large, meandering space, which includes sections for editorial, sales, art, marketing, etc.  There's a room for their out-of-print books, and a room for their newest books.  Also a reference library of current picture books from other publishers which helps in researching illustrators, and recently  published subjects.  Every editor's work cubicle is lined with shelves, holding piles of books in progress.  Boxes of new books, fresh from the printers, took up floor space here and there.

There's a lot of creating going on in that building and it was fun to see and imagine!