Is Sundays busy always during holiday season? Which day is best or does it make no differance? What about the lines? Will do park to park for one day becasue I and my family plan to visit other 2 days at Disney during the 8-day stay in Orlando. Never been to Unverisal studios before and I have a child who is a hard-core Harry Potter fan and that she does know this is her 18th birthday gift.