We went last week because my DD11 asked to go to the castle and I said no. I picked Akershus instead. We did not have the dining plan, ended up being $290 with the tip (3 adults, 1 kid, a couple of alcoholic beverages). My daughter enjoyed meeting princesses but I wished we did just about anything else for that much money. Food was good, but not great. There are many other restaurants I think we would have been happier with - and those probably wouldn't have cost that much.
My daughter wore shorts and a tank top, with her Ariel ear band. She no longer has any princess dresses that fit, and the "feels like" temperature was 100 degrees. I didn't feel out of place in normal hot-weather park clothes.