We actually have IOA and USO tickets for that day, (the main vacation is WDW) so when we get settled in our resort we're heading out to start the day.
Last time we went, we arrived around 2 and had enough time to see all of IOA, so we added a IOA/USO Express Pass tickets this time around.
So essentially, we'll be there AT re-opening for HHN.
My personal touring plan would be to start the day in USO and hit the major attractions with our Express pass, then move on to IOA while we wait for HHN. Is that doable?
How does that work? Do they kick people out of USO & corral them if they have tickets to HHN? What time does USO shut down to get ready for HHN? Can you go back to IOA and wait for USO to re-open?
I know it's a pretty immense amount of stuff, but we're just trying to get the most out of whatever we can for 1 day's worth.
I've only been in the studios prior to shutting down for HHN, but they will place you in a holding area, which is by the Irish bar Finnegan's between Transformers and Mummy, you can go in and eat or get something to drink while waiting. At IOA I think the crossover is by one fish blue fish in Suess Landing, they will walk you over to Universal between the soundstages that lie between the two parks.
You get about a 20 minute head start with a few houses they open at the start, you can essentially ride the wave counterclockwise around the park, and do it that way. And still probably have time for the show. The only negative is it will still be daylight when you start, and those soundstage houses are DARK. (Which may not give enough time for your eyes to adjust).