I think you'll love the resort. My son, seven, really, really liked the pool area. And just in general, walking into each of the themed areas was enough to occupy several hours for us. We typically stay at the Beach Club, but if my son had his druthers we'd be at AoA every time.
As
@SarahC97 said, the buildings are all pretty much the same. My son noticed that as you walk into the Mermaid area the building on your left is the "good guy" building and the building on right is the "bad guy" building.
I have no input on floor.
And yes, as everyone will tell you, it is the farthest section. But I mean, in the grand scheme of things, it's not that big of a deal. You get the added bonus of walking through the Lion King theming on the way to your buildings, which my son really enjoyed. And note there is a short cut of sorts to/from the bus stop, where you can bypass the main building and go directly to your room, cutting off a few minutes.
The biggest downside of the resort is the food court, often a calamitous mess.