My son is about that same age I am starting to see him losing his sweet innocent little boy-ishness as he becomes bigger & bigger. We went for his 4th bday to Disneyland & he was dressed up as Peter Pan who we got to meet that day & Peter Pan said to him “4 is enough, don’t you think?” and I wholeheartedly agreed & wished I could’ve frozen him just like that!
Anyway, double strollers, we have a double wide that is very lightweight & compact for a double wide & isn’t very long either. I can’t imagine trying to push anything bigger than it around a park that was designed in 1955 with a lot of infrastructure from that era remaining. But we see plenty of bigger, longer, wider strollers. The trickiest place to get through the gates into DL (our double wide takes careful navigating to get it through & if the CM’s have their chairs turned for any reason, we have to wait till they turn them back facing forward otherwise we snag it). Other narrow points to watch out for are: both sides of Astro Orbiter into Tomorrowland, NOSQ especially after as it gets towards the Train Station/Haunted Mansion area, all of Fantasyland behind the castle, and Adventureland in its entirety. DCA though is mostly no problem as it has wider walkways & is a great place to escape during peak crowds. What I noticed was a bigger problem was that with so many rides down the rides that were available had much higher wait times than I would have guessed by looking at how many people were in the walkways. If you’re at all going during Food & Wine, then the booths will take up space in those walkways & it will be noticeably busier making navigating a touch trickier but still better than most of Disneyland.