HP rides - Depends on when you arrive. If your planning to do VB first, as
@eyehartdisney suggested, you'll hit long lines at the HP stuff by the time you get to IOA/USF. In that case, later in the evening would be better.
If you do EPA at IOA/USF, you'll do the HP stuff in one park during that time, then you have the choice to jump to the other park at park opening to do the other HP rides. We've always had good luck doing that, but I've seen others say that by the time they got to the other park, the HP crowds had built up.