I would skip the park-to-park, especially since you are spending the first day at VB. With only 2 days at the parks, you won't really have time to switch parks. Even with EPs, we plan for 30 minutes from start-to-finish on the train.
Yes, you can ride all of the rides in a day at each park with EP, but you will not be able to do "everything" in the parks. There are just too many other things to do: shows, restaurants, or just walking around looking at all of the details. If you plan on riding no-EP rides like Hagrids or VC, then you need to make special plans for those to avoid hour+ waits.
I typically recommend 3 days at IOA and US for a first trip. One day at each, and then the third day to re-ride favorites or hit shows you missed...