Potties.
Disney is one of the better races pre-race for portapotties. If you are on an earlier bus, once you arrive at the staging area, immediately go through the bag check tents and there are hundreds located there. If you are with non-runners you can come back through the checked bag tens and talk with them. (i.e. the area beyond the checked bag tents is for runners only.
Once released to the start corrals, there are maybe 50-75 potties at the corrals. The crowd is usually released about 50-60 minutes pre-race. If you hange back at the staging area until 30 minutes pre-race the lines are next to nothing.
Once on course there are potties at most every mile point, 10+ in the early miles. Aid stations will also have them.
The numbers start to diminish as the miles increase.
Want real facitlies? Epcot will have them inside the front gate, both sides; behind East Innoventions and in the Odessey Building. Also, I believe that Norways facilities are open but you will need to go beyond the corner to the backstage area.
MK Mainstreet, about halfway down on the right, Tomorrow Land just after we turn left and across from the Indy Track, Behind (and just before) Pooh and just before Country Bear Jamborie
AK Just after we hit the inside of the park and the left (a great place for a breath of Air Conditioning) , near Everest and then in Dinoland
DHS Commissary Lane its just past Streets of America
Epcot the last time forget it, too close to the end
Now for the Retreat
I have never used it but I can see where a first time runner may like it. Though friends who have used it spend little time there. Its big draw in my opinion is the easier bag check, a character encounter and a chance to head to the start line earlier. 2010 was the only time I considered using it. It was open until the 10 day forecast was public. Once it became clear that a really cold weather pattern was about to set in. I hear that while protected from the weather, the tent was not all that warm, either. I say if you have any desire for some pampering then go for it.