I have a 13 x 9 mudroom/laundry combo. I wish it was 3 times the size. I would never make the laundry smaller.

With the plan you posted I would remove the wall between mudroom and laundry because you gain light with the window in the entire space. The closet can then be backed up against the pantry wall with a loss of only 6 inches. The door could move over to the end of that same wall. A front loader pair would provide counter space over the w/d.

I would not want a wall sectioning anything off because what's lost is great space for whatever in the middle.

I like Rococogurls suggestions. There could be an island in the center for crafts, sewing, etc. too. Though, that may not suit your needs.

The kitchen though, have you considered having the kitchen forum look at your plan. There are some real experts over there. The reason, is that I see some things that look like they might need rearranging for more efficiency. I am not a kitchen layout expert, but over on the kitchen forum there are experts, and very kind and helpful experts. For instance the location of the stove, between the sink and the frig, is possibly awkward.

Back to the laundry room. You'll need room to store supplies, and more. You will need hanging space to dry items. You'll need a counter for folding. You'll need easy access for the dryer vent to clean periodically. You'll need access to quick shut off of water in case of leaks, or when leaving for vacation. Any cabinetry at the machine area, needs to allow for machine maintenance and pulling out the units for repairs.

It looks like your current plan locates the set against an interior wall. How will the dryer be vented? It would be better to locate the dryer against an exterior wall for the shorted ducting you can get. Dryer vent spec installation varies between brands. The manual will spec length of run that is desired. If it is too long of a run, then an inline exhaust dryer fan is recommended, I believe. When there is a 90degree bend, that = 5' of your allowed run. So you can't put in very many elbows before you use up all your length. My machine is 8' away from my exterior wall over the basement, where the duct runs between the joist. Because of all the bends to get it 4' down into the floor, then out the exterior wall 8' away, I used up 33' feet in the equation. The vent on the outside of the wall = 10' of ducting I believe. I could be off on some of these numbers, but it needs to be considered when locating a dryer.

Depending on your exterior, you could put them under the window in the upper right 45 degree angled wall. But you don't want the dryer vented onto a gathering area, like a patio, cause lint will blow out. It's best to have the front loaders against a load bearing wall too.

When machines are placed on joist flooring system, they need to be near the end of the joist. Otherwise there is tendency to bounce the floor. Unless you are on a slab of concrete, that is ideal, and the machines can go anywhere. The machines need to be able to be absolutely level once installed.

Enduring, thanks so much for all of that. I will read through it more thoroughly regarding spacing, etc. In regards to the kitchen layout, YES! I have posted it in both Houzz and Gardenweb forums and we will be totally changing the layout :)

I don't know much about the Houzz portion. I've been a member of GW, and there are really good people on the GW side of things. It can be tough love sometimes, so be prepared. But the finished products are raved about by the OP, once done!