We definitely prefer the one floor GV. We have stayed in the one floor about 6 times now, and this last trip we requested the two floor, just to try it out. The one floor seemed much larger. While it was a beautiful room, There seemed to be a lot of wasted space in the two floor. The Washer/dryer was upstairs in the hallway, while the one floor had a whole seperate very large laundry room with a sink and counters for folding.
The living room in the two floor seemed to close to the dining room table. In the mornings, we usually have guests stop by, have coffee etc... at the main table. There is plenty of room, to not disturb the teenager sleeping on the pullout in the living room. While with the two floor, it seemed too close. Don't get me wrong, the two floor was nice, but we just love the one floor.
The one floor had two entrances to the room. One main double door entrance, with a seperate door down the hall where the two studio rooms were. This was nice if you had any late night arrivals from Jelly Rolls, and noone would be disturbed. I could be wrong, but it seemed with the one floor, you had the whole floor on that side of the building. We usually get about 4 to five rooms for friends, and all meet up at the GV at night, or in the morning before hitting the parks. One night we had at least 30 or so people on the balconies enjoying the fireworks. When we had about 20 people over for chef cooked dinner this past trip in a two floor, it seemed a little cramped.
I think you'll like the two floor, but love the one floor. Good luck.