Crowds? Let me tell you about crowds lol. We did Christmas week this past December and it was packed! But we had the best trip ever. For some strange reason, we love the crowds! All 4 of us! We were at Disney 3 days before and the week after Irma (see link in signature) and it was empty. Completely empty but .... we had a better time when it was crowded. I know, I bumped my head. Anyway, we have a trip booked for this month, April 20th - 28th. It's our very first Spring Break trip and I have a feeling it wont be as crowded as most spring break crowds. For some strange reason, our school district has our spring break really late. After the kids return they will go back to school for a whopping 18 days then it's summer break. really! I have no idea who did the calendar but they really need their head examined. OP, I wouldn't worry about the crowds so much because if you have your FP+, ADR's and a good touring plan you will be fine.
Here's something to help your stress lol
Christmas week 2018. Dec. 27th to be exact in frontier land MK.
View attachment 392784