Thanks to all of you who commented on my prep sink question. I've attached a buggy (sorry) 3D layout and I'll list the key exact dimensions.

We are a family of four, two children aged 2 and 5. One cat (Sochi). The house is a narrow urban lot. We plan to live here for the next 16 or so years.

The kitchen:

is 17'4" x 13'6", running from the edge of the peninsula to the front of the fridge/pantry wall (17'4") and from the sink/window wall to the long wall behind the cooktop (13'6"). I've also attached a drawing with a 15" overhang off the peninsula - this overhang is technically in the dining room space, so this 15 inches doesn't cut into the 17'4" space. If we include this whole space as kitchen space, the kitchen becomes 25' long.

The Island

I've drawn in a 5' x 26" island with a modest sink (I'm thinking 18" by 14" sink, approximately. This will handle the big pot that I use almost daily).

Aisle clearance

This aisle between the island and the sink/window run will be 48". Note that the kitchen is in the middle of our house and there will be lots of traffic going through here.

The aisle between the island and the cooktop will be 38". Note that nothing opens along this narrow aisle - no oven or dishwasher and little through traffic. The dishwasher remains on the main sink run (although I'm considering a dw drawer on the island).

The aisle between the island and the pantry/fridge run will be 48". Regular traffic here to the fridge. Note the door next to the fridge leads to a crawl space basement, rarely do we venture down there. The stairwell landing will function as a broom closet.

The wide aisle between the island and peninsula will be 75". The oven is on the peninsula. If I turn the 5' island into a 6' island it would still leave about 63" between the island and peninsula.

What do you think of my aisle clearances?
Would you be inclined to do a 6' island? 4'?
Is a 26" deep island going to look silly??
Should I have a dw drawer on the island?
Other issues of concern?

Explanations of the space: the kitchen is narrower than the rest of the house because of a courtyard behind the main sink/window wall. This brings some light into the back of the house (lr and dr) through large windows. To the left side of the courtyard is the dining room. The dining room table that comfortably seats 8 is there, tucked out of sight from the kitchen for the most part (except from the peninsula). The sunken living room opens up beyond the dining room. To the right side of the courtyard, just at the end of the pantry wall, is a breakfast nook. It opens into the play room/den at the front of the house. The breakfast nook is only 6'8" x 7'6". It will probably serve as a snack and craft area for the kids. We eat family dinners in the dining room.

Some here have suggested that I do away with the peninsula and have two bigger islands instead, with a long run taking up much of the 25' wall, and turning my sink/window run into a pantry or desk area. I think I still prefer to have my sink hidden from the living room and dining room by that short wall, and I think a 20+ foot counter run might seem too much (thoughts??)

There is cabinetry above the speed oven/micro on the pantry wall, but I couldn't get the software to put one there. Also, I can shift the cooktop to be opposite the island sink.

This is my cabinet makers drawing, no island yet, but is shows the space behind the peninsula a bit better.

dcfixerupper - I'm not sure, it was on my husband's pc. I'll ask and get back to you.

I think the island would look better centered on the range wall. it looks out of place all the way towards the frig wall.

Based on your previous post, it does seem that most of us don't think that you should have your clean up sink on that courtyard wall, but you seem hesitant to move it. In that case, I would think adding the island with the prep sink should help. I would just make sure the prep sink is big enough to drain pots of boiling water, which it sounds like you've thought about.

I know modern cabinets often have zero counter overhangs, but with 1" overhangs, I got a pair of 42" aisles if they were equally spaced - counter edge to counter edge. If one becomes 48", then the other becomes 36". It is beneath the recommend size for a working aisle (42") and I'd have some concern about it. I also have a little concern about the ref door and the aisle width in front of it, but that may be an artifact from the perspective view.

I'd be tempted to rake the side edge of the walnut bar so the part towards the wall was 8 to 15 inches deeper than the part at the end of the peninsula. Two reasons - it'd give a deeper project space for kiddos, and it might look cool.

I don't at all understand the 6 ft space between the island and the peninsula. That's huge. I would add the foot to the island length, and then shift it, or adjust the size so it had equal aisles on each end, with no more than 54" for those aisles.

I wouldn't center the prep sink on the island, but have it toward the fridge so most of the island is a clear, large workspace.