I did it today and yes, you can. I bought also the express queue. I have enjoyed each of one attractions without any queue. I started it from the Universal Studios (around 9:00) then I got the train in Hogwarts to the Island adventure (around 2:30). In my opinion its worthy the price and the money!
Get a taxi download the app liyft so cheap it costs about $20 to park long queues in and out get taxi to city walk drop off save yourself the hassle
It you do that, you have to run and maybe you won't see everything. I did one park each day, and now I have to rest...hhhaa
you could get in 2 in same day ..... but 2 b less stress & make da most of it 1 id say is groooove 👍
Go early and start with islands of adventure first, get hogwarts express into the other park on same day.
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