If you can move the door to the end between the wet & dry areas, it would be good. You're wasting valuable counter space to have the door where it is. I suspect you cannot move it, however.
Maybe rotate the enlarger 90 degrees to allow a full counter along that wall, even if you have to have a fold up counter across the pocket door, you'll need more dry counter space for such things as loading sheet film holders, cutting paper down to size before enlarging, etc. You may also want a 2nd enlarger, if you do 35mm work frequently. Sometimes it is just a pain to reconfigure the enlarger.
My work with a Zone VI enlarger trying to print 35mm was a disaster--the lamp was too dim (97% of the light was falling on the negative carrier instead of the negative in this format), the bellows wouldn't compress enough for small enlargements from 35mm. I realized that it is difficult to make one enlarger for all formats, and even if it does, it's probably cheaper and better to have one for large and one for small formats, if you can fit it in.
Put a counter from where the enlarger is, to at least the pocket door and rotate the enlarger so you face the front of it as you are in the aisle. As it is, you'll have trouble dodging & burning in from the left side, as it's boxed in by the wall.
I designed my darkroom in a similar sized space. Instead of the water heater/furnace, though, my wall had a 45 degree bevel along a similar space, creating a similar problem. Think about this: you can probably pay for anything else you want or need to make the darkroom function well, EXCEPT SPACE.
I thought long and hard about my design, and took at least a few months to think it through. One thing I came up with was this: I was trying to put a 30" deep sink in it, and it made the aisle too narrow. I settled for a 24" wide sink, figuring if I ever wanted to do 16x20s on a regular basis, I would spend the money for stainless steel trays, which (though expensive) have little wall thickness and allow tighter spacing. I settled on an Arkay fiberglass sink--though more than I wanted to pay, it works.
It is important that you work out your tray arrangement using the actual inside dimensions of your planned sink--a couple of less expensive plastic sinks I looked at had protrusions into the main area for mounting faucets--those would have prevented using big trays along those, and a 6 ft sink would have allowed only 2 16x20 plastic trays (oriented in landscape mode). Plastic trays have a wide lip, and limit your use.
Make sure your groundwater temperature summer & winter is low enough for the temperature control to regulate--I was considering one, but found (I live in the San Francisco bay area) that the water temperature in the summer is too warm to allow a regulator to work. I saved some money by not getting one! They need cold water 5 to 10 degrees cooler than you lowest setting to regulate. Check the manufacturer's specs.
Good luck with your design.
