WHEW !
That's a lot of info but you are right in planning ahead.
I am going to use Chubby to answer your questions from my prospective.
He is 120" long 67" wide out to out and 5'6" tall. So he is real close to your plans.
My galley is 18" +/- deep but the flip out feature makes 9' + of counter space. I have tried all the cook tops but find my little 2 burner propane cooktop is a hands down winner. Gets HOT quick and controls well. The fact it is not built in (just bungi corded down for transport) lets us have infinate possible choices when cooking. We have used it on the picnic table , my campchef dutch oven table and of course on the tile topped swing out counter top. Electrical items in the galley I have found most useful are lights of course , a toaster oven for hot cinnamon rolls , biscuits , and toast as well as to reheat leftovers. We toted a microwave on one trip and I gave it away. The single most important electrical appliance ( please don't laugh) is our red neck hot water heater. A 32 cup large coffeemaker.
I plug it in as soon as I am up and in 8 minutes I can have hot chocolate or coffee singles or hot tea. Washing greasy dishes in cold water is a fruitless chore. Having hot water on demand for the cost of a used $6.00 coffeemaker from Goodwill is almost decadent. On our second outing we invested in a 10 x 10 first up gazebo. This was the single most important addition to the build. It provides shelter from rain, snow, cold winds, and the beating sun. It is infinatly flexible in that it can cover the galley or act as a privacy room , living room or an extra kitchen area.
The hinges I used on the hatch were off the shelf stanley strap hinges and by cleverly covering them no runs, no drips, no errors, opps I mean leaks. I have pressed the small bathroom grab bars as the ultimate handle both inside and outside of my builds. The little blue 5/6 gallon water tote jugs have been all we have required as we are generally in state parks. When we are boondogging we keep back up ice in a seperate cooler and used the water from that cooler as well for pottable water. As to cabinets, you can not build in enough. My wife gave me two stanley plastic tool totes and I pressed them into service as a dry box for dry food stuffs and a utensil box for the small camping tools and toys. I built my hatch full width with a 1 1/2" overhang and have had no problem with rain and water infiltration. One thing you didn't ask about is cooler in or out of the galley. They are a space hog and we choose to use the open space below as a staging area for the pots and pans and other needed cooking items so the cooler sets out close by but not IN the galley. My album has a ton of pics on 4 builds all are vastly different and work well for different reasons.
We have found chubby ( my first full sized camping build) to still have our favorite layout and functions fantasticly for our style of camping. Hope you have as much fun in your build as we did.
