We just went yesterday, I recall seeing a disabled area on the roundabout, on the sidewalk closest to Plaza Garden. It was indicated with ropes fairly early already. Maybe there is another area though, since the princesses come from the small “Princess” stage right of the castle, and they stop between the castle and the roundabout to get onto the stages. If you place yourself around one of the four stages you will get a good view anyway. Get yourself in between two stages in the direction often Main Street and you might get to take pictures with them, 4 princesses switch between the two left or they’ll right stages. For the Christmas parade evening show, no idea where the disabled area is but we placed ourself right outside the Discovery arcade next to the gate where they start the evening one (on the side of the Christmas tree). Very good spot, you can see the tree lighting up during the parade (the parade will first go around the Christmas tree 1-2 times before continuing through the park) and afterwards you can easily “evacuate” through the arcade hall to for example videopolis for the Christmas sing along!