I've never been to US or IOA and we're going the 1st - 4th of December. Is one day at each park enough to see/do everything? I'm planning 1 day @ US, 1 day @ IOA & 1 day @ Sea World - that should be plenty, right?
Yeah, you will be fine. We went the second week of December a couple of years ago on a Universal only trip. We had a 2 day park hopper and basically accomplished everything the first day. The second day was full of rerides on our favorites. I am fairly confident that you will be set.
On my first trip to the parks I went in January when it was very quiet.
IOA - We spent 1.5 days there although we had actually ridden everything within 3 hours of the park opening. We just liked it so we went back!
US - Spent a full day there although we could have done it much quicker if we had planned the shows a little better. I was determined to see Terminator 2 3D but kept missing the start!
SeaWorld - Spent a full day and needed most of it to see all the shows but it was still a relaxed day.