I'm honestly clueless as to where the starting point of this puzzle is.
This one I did by working in from the corners, look out for places where a black cell would force a line of whites over three rooms. You may need two guesses sometimes to progress.
One year down the line, and I still can't solve this.
Two and a half years later, I ended up solving this one with heavy, HEAVY 4-level bifurcation.I think I definitely missed the intended break-in.
Really well done, I'm impressed by your perseverance on solving this one. After two and a half years I think I'd have long forgotten about it. I promise not to publish anything this evil in the future!