We switched from the double when my kids were 2 and 4, to a single that they could share at 4 and 6. I took it until they were 7 and 9, and was glad I did! They both became ill (one had strep throat and the other had a major ear infection) on the same trip! Both had high fevers, too! DD fell asleep in it at DHS, and I had to push her back to our room at the Dolphin (she could stay in it on the boat, thankfully). Without it, I don't know what I'd do, as she had a fever and needed to get back to the room (we had a doctor come to the room, which was also a great blessing).
So, if you are driving anyway, and have a stroller, I'd bring it just in case. You may or may not need it. I think rentals at the parks are expensive, but they are handy, as one trip when DD turned 8 I rented one a couple of days for her (she even fell asleep in it, she wears out easily and could sleep 14 hours on vacation).
I personally liked having it just in case, although my kids at home hadn't used one since they were maybe two. I kept our good single one just for Disney! I am almost sad to see it go (giving it away next week or so). Such a good "friend" it was to us!!!