We started out visiting family so had a car. We parked it when we checked in, and didn't use it again until we checked out 3 days later.
The walk to Universal is 5 minutes along a beautiful palm tree lined path with no crowds. IOA is a few minutes more, and at night we walked over to Citywalk. The stay at HRH was so much better than we expected, that we're hoping to go back next year, and I don't think I would take a car next time.
Glad to see they have the shuttle to the two other parks. We didn't have time to go there, but now we know, because we will definitely stay longer next year!!!!