I am able to answer multiple things for you since I went to Universal for the first time ever. I stated at Universal Deluxe hotel before staying at hotel on Disney property.
The Disney from Disney to Universal is not a far ride like
@bhg469 mentioned.
There is not such a thing as a Harry Potter park. Both Universal Parks have a Harry Potter Land. Universal Studios Florida has Diagon Alley and Islands of Adventure has Hogsmeade. You are able to do both Harry Potterlands in a day by using Hogwarts Express from Diagon Alley to Hogsmeade or Hogsmeade to Diagon Alley with the catch of you needing a parkpass.
I am a fan of Universal's type of a fast pass system, but there are 3 things about it.
- You have an option of Express pass and Unlimited Express pass. The Unlimited Express pass is 1 difference from Express pass with it being Unlimited allows you to do the same ride multiple times in a day besides doing almost all the rides in Universal Theme parks in Florida.
- You are better off staying at a Universal Deluxe hotel if you want to use Universal's fastpass system due to cost. If you stay at a Universal Deluxe hotel, you get unlimited Express pass for free for every day you stay at that hotel.
- You can't do all Harry Potter attractions with Express Pass. Hagrid's Magical Creatures Motorbike Adventure is a ride that you can't use Express Pass on. You can use Express pass for rest of the Harry Potter Attractions as along as its not Hargrid's.
Instead of Express Pass for Hagrid's Magical Creatures Motorbike Adventure, you need to use standby line or Virtual line reservation.