Sydney has been in a big girl bed for a week now!
Back around the time she turned 2, we talked to her about taking the side off her bed so that she could get in and out by herself. Her reaction was not what we expected. Rather than eagerly pursuing the idea, she got very upset and made it very clear that we were not to touch her bed. ...so we didn't.
Then last weekend, Meghan broached the topic again and Sydney liked the idea.
We've got a rail that goes most of the way across the side so she doesn't fall out, but aside from that, she's free to climb in and out. To our surprise, we haven't caught her wondering around at night and she hasn't come into our room in the middle of the night. So far the transition has been very easy.