Reed got his twin-size bed today. We are still shopping for a headboard and so forth, but the mattress and frame are in place to see how he does. Fortunately he has already learned not to roll very much in his sleep from using the crib as a daybed. We felt he would do just fine and not fall very much on a bigger bed.
He was super excited to help me move his crib over to the other side of the room, and then bring the parts of the new frame and the bed into his room. Once we got it set up, the steps to get up and down that he got from Aunt June (a loooong time ago), work perfect to for climbing back up.