I'm not sure I understand your comments. How is going on a bus is so different from getting on the monorail or boat? Aren't they sort of similar? To get to AK and MGM from the Poly, you still have to take a bus. Of course you can always drive, but that is true of all the resorts.
No matter where you are staying, you can eat anywhere on property that the plan allows. In fact, the food courts offer easy choices in the morning - because everyone can pick what station they want to eat from...as opposed to having your family eat at the quick service restaurant at the Poly, for example, where the choices are considerably more limited. (We like quick breakfasts mosts days). I consider it one of the downsides of staying at the Deluxes. Now in the morning I'm not going to take a bus from the Poly to Pop just for breakfast if I'm going to the MK..but if I'm staying at Pop, I might just have breakfast at O'hana's on my way to the MK, so I'm not quite sure what you're getting at. Do you limit your dining to the resort where you stay?
In any event, to comment on the orginal poster..if you get two rooms, you'll either have to split up the adults, or put the 12 year old by herself, or put the four years olds in their own room. I'm not sure I'd feel comfortable with those options. If the kids were older, yes, but probably four is too little. On the other hand, most places won't legally let you have five people in a room, unless one is in a crib. If the kids were older, then probably the extra bathroom would be a big help, but the two little ones probably require help bathing and relatively constant supervision, so for now, the extra bathroom might not be that big of a help. It's a tough choice, but I think I might go for one room. Have you considered a cabin at Ft. Wilderness?