Was there last week. The middle of the week it was totally manageable and nothing to even worry about. Maybe 30 at most min during the day- one evening it was practically a 10 minute walk on. On average, I'd say were were on within 20 each time. Wound up riding 6 times during the week. On Friday night it was fuller, like 40 minute wait, on Saturday the park was full and it had about 90 min wait (everything Harry Potter was like 2 hours+). Granted that was apparently an unofficial Harry Potter celebration day or something, so maybe things were a little more intense than normal.
I'd say during the week, you should be pretty fine, and make a point of riding away, as once the weekend hits, it gets dicey.