You can attack it from a couple of different angles... If the crown is all the same, then you can consider it all "room crown", and you can then paint it all creamy white. I have seen instances where the crown is all the same and the color simply transitions to blue at the soffit-to-cabinet crown miters. Your choice. I prefer to make the two crowns different though, making the cabinet crown smaller than the room crown. With the cabinet crown minor to the more major room crown, cope the cabinet crown to butt into the room crown. Paint the room crown white and the cabinet crown blue. Much depends on the size and styles of the crowns, etc, how they meet up, how they relate, etc. But it really boils down to your personal preference. The good news? It's only paint. Easy to change if you decide to change your mind.

How about a really dark color? Or else cherry on top (whipped cream optional LOL) and make transition to white back at the walls (same profile)? Someone else has thread about transitioning CM color but I haven't seen any replies to that.

ffjunk, of course it's a personal choice, but thought I should add, we have a situation similar to yours, with a pass-through window between painted cabinets, as well as a pocket door between a cabinet and a cabinet pantry. Our cabinet crown molding, and our whole house crown molding are the same heights, but different cuts, so the choice was easier for us - keep the same crown molding throughout the kitchen, though it is open concept. We are using stop blocks at the pocket door crown as the pantry is a stained along with the crown molding above it, and the cabinet adjacent is painted, along with the crown above that. The trim around the door will be painted the same as the cabinet/cabinet crown molding. Our ceilings are 9'. We are also using a stop block where the whole house crown meets the kitchen cabinetry crown - it would be very difficult to both cope and scribe the crowns to match and we prefer the stop blocks. I don't have photos as we are still in the midst of remodeling and our cabinet maker has yet to bring and install the stop blocks.

You use the kitchen crown around the whole room. Or you use the room crown on the cabinets. No cheesy plinth blocks and 2 different crowns.