So I posted this in kitchens and am now thinking perhaps I should solve for the plumbing issue first.... I deleted what wasn't pertinent to plumbing...

Hi ya'll happy spring.
So wish I could enjoy it right now but am MISERABLE over my kitchen design disaster. Existing kitchen is horrible - teeny tiny and very awkward layout. Housewas built in the 20s, We can't move any exterior walls, windows or doors. I

Current " design" for dining (which is meant to be a formal) and kitchen attached.(hopefully you can make it out)

Existing walls are in bold black except for the existing wall between kitchen and dining room which is in gray.

I am not at all happy with the diagram I have drawn now (btw orange lines are conceptual new walls and each box is 3" x 3") and am quite certain that I am breaking all kinds of rules of good design. The refrigerator is in an awkward place and I am really struggling.

(if you click on this it may be easier to see than the photo below)

Originally I wanted open up the side of the gray wall with the existing entry way and push an island or partial island out about 2-3 feet into the dining room on the existing interior wall closest to the hall and put a sink or a stove in the middle. DH says we can't do that because we will destroy all the floor joists trying to get the plumbing to the sewer pipe or to down vent a stove both of which would need to be at the long back wall where I have the sink now. Our floor joists run from left to right across the dining room kitchen area.

The yellow area is where we are adding/moving a powder room. That is currently a very, very cramped "eat in" area in the kitchen.

Is it possible to consider running the sink drain pipe from the proposed island area that would be directly in line with the center of the exterior door entryway to the kitchen to the right of the diagram and connect in to the drain for the toilet/powder room or is that breaking all kinds of rules. I assume it has to connect into the sewer drain at some required slope level. Is there some rule or guideline that it can't run parallel to the floor for some certain distance before it connects into a sewer drain?
Am I asking really stupid questions?

Any feedback, suggestions or therapy would be greatly appreciated!

Many thanks in advance!
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