We were at the YC for our first visit with an infant in December. He was 22 months. You can ask for either a crib or pack 'n play. We requested a King and had the perfect amount of room for the three of us. We rely on Disney transportation for everything. (live downtown Chicago so we are used to mass transit and our son loves it - still talks about the monorail, bus to MK, etc, on an almost daily basis). Two best ease of travel trips:
On the bus, I would usually carry our son or put him in a carrier while my DH dealt with the stroller. Then when we got to the parks it was so much easier to get through security. I would put DS in stroller with no bag or leave him in carrier, and push empty stroller and walk right in while DH went through security lines with bags. This worked so well for us. One less line for our son, and somehow the stroller going through security even if prepared ahead of time, took more time. (this was immediately before they implemented tighter security practices though)
ANOTHER HUGE TIP - use an umbrella stroller with a basket. Honestly, this was the BEST decision we made and dramatically impacted our trip in positive ways. Not to go 100% off topic. But all day long we saw tons of parents struggling with strollers, kids, bags and the buses, etc. (actually witnessed a massive fight between two families on the bus back to the YC/BC about their strollers, bags and the kids taking seats on the bus) We NEVER had any issues. We took a nicer umbrella stroller that folded up in seconds easily, extremely light and we would just pop on and off of transportation with ease. We could also navigate even tighter spaces/crowds with ease. We were stopped numerous times by other parents telling us they wish they had done the same and wanting to know our our stroller make and model. This worked for us because naps we not in the stroller but back in the room. (for the record, if renting a stroller, our "stroller" is the city mini GT at home which we LOVE, but does get really heavy quickly. We were so happy we left it at home). Our stroller "footprint" was much smaller and it did make a huge difference.
Look into Uber Family. I thought I read that was now an option in Orlando.
At SAB there were always tons of buckets and shovels laying around so thankfully we didn't bring anything from home.
We brought all of DS snacks from home. Usually he shares our meals, but the few times we had to get him something for dinner separately, we ended up at the Boardwalk Bakery. Check out the kid menus in the area since I was surprised they offered different options. (Mac and Cheese at Boardwalk, but not the Marketplace, etc). I could not find whole milk anywhere.
Let me know if you have any other specific questions.