We have stayed at SSR a few times, it is our home resort, and we love it!!!
You will read many different opinions on the questions you asked, so think of your first trip/stay at SSR as a learning experience to get acquainted with the resort.
The Congress Park area is the closest to DTD if you plan on walking. The resort is pretty spread out, but beautiful, so we love walking around. We find it no big deal to make the 5 minute walk to the main pool, and check-in/restaurant area. We have never stayed in the other buildings, but they are all fairly new (Grandstand is the newest).
I love this resort. We use the quiet pools a lot, and since I like to golf, it is great to just grab the clubs and go over to the clubhouse. A big plus for me. Walk over to DTD in the evenings for dinner too.
Just enjoy and get a feel for the place, I dont think you can go wrong no matter where you stay. Good luck