Here are plans for Portland. The top part of the plan is very similar to what is already in place. Everything to the front is new. I hope to make Portland a lot more water front. This will include the barge (car float) and hopefully three other wharf areas.
I did a preliminary set up and all looks good, but things might change a little as I get started. My biggest worry would be over loading Brunswick yard. At the moment I'm using the old sawmill tracks as a temporary barge. It doesn't do justice to the real thing, but I get a feel for what will happen to the yard.
Since I made all the changes to the upper and lower level, I added about 25 cars to the layout. The good news is that at least half won't get into Brunswick. So maybe it won't be a problem.