You can most definitely pool hop.

HRH has become the most popular resort on property. It's often more expensive than Portofino Bay. IMHO, Portofino Bay is the nicest of the 3 resorts, followed by HRH, then RPR. If you're familiar with WDW resorts, RPR would fit in a similar category as WL & AKL. Still a deluxe, but closer to the moderates than the other deluxe resorts. Why is HRH most popular? Location, location, location!!! I don't know if you were aware of it or not when you stayed there, but you could have walked to Universal Studios in 5 min. from there. IOA is another 5 min. through CityWalk. From HRH, you don't really need the boat. It's actually slower, unless you're just in the mood for a relaxing ride. You can also walk from RPR, but it's a little further. We stayed there once & took the boat most of the time, but did walk occasionally. (If I were in better health, we probably would have walked more often than not.) From RPR, you're closer to IOA. The walkway comes out at Margaritaville. As a pp noted, the rooms are bigger at HRH. RPR doesn't have a pool slide, but does have a nice water feature. With the pool hopping feature, it isn't that much of an issue anyway. HRH is more lively (which is popular with preteens/ teens), while RPR has a laidback island feel. All that said, I don't think you'll be disappointed with RPR. I'm sure you'll all have a great stay.