With Express Passes & Park hoppers, you will be able to hop between the parks quite frequently. Unlike Disney World, Universal Studios Florida & Islands of Adventures are literally next door to each other. You are going to have a blast! Be sure to stay around for the Mardi Gras parade, your son will love it I bet.
Those were all major factors in us doing Universal for this trip. Universal offers so many added conveniences over Disney, and it goes without saying it is going to be way less expensive than Disney would have been.
When you get closer to the trip, I HIGHLY recommend getting some dining reservations for some of the City Walk (the shopping/dining area just in front of the parks). While not as crazy as the Disney ecosystem on getting reservations (can literally get them a few days in advance), it will be busy since it's spring break.
Here are some we highly recommend: Cowfish, Vivo, Antijitos, Bigfire Grill & Chocolate Emporium (your son will love it)
Btw, tip on Chocolate Emporium (for you & lush ) - The food is ok, but huge portions. We split a salad with this almond chocolate bread last time and was really good. So keep in mind. But the thing best there is the atmosphere and of course the shakes / sundaes. You can even get those without actually sitting down to eat.
I actually made a reservation for Toothsome's for the final night of our trip back when I made the hotel reservation. It was very nice to not have to do the Disney thing of waking up at 6am 60 days in order to do the meal reservations. I have some other meal reservations booked as well, but your additional restaurant recommendations are definitely appreciated.
Volcano Bay is a blast and so much fun. I recommend trying to start heading over at least 30 minutes before Early Hours even begins. Given that the bus from Royal Pacific only comes like every 30 min to VB, I'd kinda recommend maybe head out of your hotel room an hour before. All of the VB is so much fun, esp for the lazy rivers and aqua coaster slide. Make sure you bring a towel from the hotel!!
Btw: For Pool hoping, I think you need to ask the lobby check-in person for a pass for that or to activate it? Idk how it works. I tried it once and our key didn't work (from Aventura -> Cabana Bay). But luckily it's easy to get in via heavy bag swung over o hit the gates lol.
Oh good catch I forgot about this! You bring your key card with you to the hotel you're going to hop to and that's where you get it activated.
These are great tips. Regarding the VB buses only running every 30 minutes, do you think it would be feasible to walk there from RP? I have read that Cabana Bay and one other hotel (I think Adventura?) have pathways directly to VB, and Royal Pacifc is close to those, but it is hard to tell if the overall walk would be worth it.
Regarding pool hopping, that's definitely one of the things I'm hoping to work out with the concierge on our first day. There are a bunch of little things that I'm not totally sure how they work with universal. Like, apparently I need to pick up physical ticket lanyards instead of it just being linked to my hotel room? And a second physical lanyard for photo pass? I have seen conflicting answers about both of those. At Disney that stuff is just automatically linked though my Disney account and magic bands for my family.
One more question about Volcano Bay: Will my existing express passes (from my hotel reservation) apply to VB? I have seen conflicting things about this as well. I have seen that it has its own system with the taputapu wrist bands, so I don't know how much express pass would even matter for that park, but it looks like some version of express pass does exist there.