I intentionally (and unashamedly) hid MMRR's very existence from DS4. He's completely obsessed with trains (don't even talk to me about WDWRR being closed, he'll hear you!) and totally adores the new style Mickey animation. I wasn't sure we'd be able to get FP+ or even if it would be on FP+ at the time.
Fast forward to planning our FP+ selections, and I ask my kids what the one attraction they most want to go on so that I can prioritise it. I hear an excited, "Mickey and Minnie Wunway Twain!" before I finished asking my sentence.
Still no idea where he heard about it. But DS9 and I are going to have to have a very serious talk about responsible YouTube viewing. Anyway, a longer trip should get them easily. I'm hoping the attraction is reliable enough to push through a lot of guests to free up a lot of same-day FP+ refreshes.