Unlike adults or older children, little ones that age just don't LIKE big 'surprises'. The anticipation of the unknown we enjoy just creates terror in pre-schoolers.
We 'conditioned' our 4 year old grandson with YouTube video's of the rides he could potentially go on....and that was pretty much everything that his height was going to let him ride. Fortunately he's a tall boy, so very few rides were off the table.
He was VERY excited to watch the videos up to the time we went.......and when we actually RODE them, his excitement was even greater as he already KNEW what to expect, and the thrill of the actual ride just added exponentially to the event.
I wish I had taken a picture of his face when Soar'n started up. PURE joy, plain simple!! He pointed out each scene as it occurred, and was ABOUT to occur as he knew what to expect. The adrenaline rush of the flight was just that for him.....a wonderful experience, and not an 'unknown' for him to fear!
He's now a HUGE Big Thunder Mountain Railroad fan (rode it 4 times this past February), and lately he's been REALLY studying Everest videos, saying 'I'm riding that!' every time he sees it.....and you know, I think it's going to be HIS favorite over BTMRR after he rides it next February.....and he won't turn 5 until next April!
Heck, I figured Dinosaur would bother him, but he just identified the dinosaurs as we passed them (he has books about them at home), and once we finished the ride, simply said, 'that was fun! What's next?' He also had watched the YouTube video many MANY times. We rode THAT one 3 times before our vacation was over!
So, condition them now before you go. You'll be pleasantly surprised how they'll react to the real thing, as once they're comfortable with seeing what to expect, those rides are already an old friend before they even get ON for the first time.
I'm not suggesting this for older kids, though. Apprehension and expectation is all part of the fun.....but our little guys aren't quite ready for that 'jolt' yet.
Been there, done that, SEEN that, and it worked for our grandson!
Regards! Michaelson