Depends on where you are staying. At 2, my son still slept in a pack n play at Disney bc the queen beds at CBR were too big for him, and the murphy bed was too high off the ground. He was so tired that he was fine in the pack n play.
At 3, we did a split stay between OKW and the Polynesian Villas. At OKW he slept in a queen size bed with rails. The rails stretched almost the entire length of the bed, and he was absolutely fine. At the Poly, the murphy bed was perfect bc it was so close to the ground.
My daughter will be 18 months on our trip this summer and will sleep in a pack n play. We're planning another trip for August of 2019, and our daughter will be 2 1/2. For that trip, unless she is as amenable to being in the pack n plan as my son was, we'll likely either rent a crib from an offsite baby rental place (that's what we do when we visit relatives in Sarasota), or if we stay in a resort that has low-to-the-ground murphy beds (the POR resorts maybe?) she can just sleep there.