C.W.
My daughter used to do that. If I didn't rock her she'd play in her crib and go back to sleep at 5. I was going in there rocking her and trying to feed her. I started waiting to see if she'd go back to sleep and she would wake up and start playing in her crib. I eventually played a lullaby music cd that I didn't think sounded creepy (she seemed to respond to music I liked/disliked lol) and at 4:30ish she'd wake up and I'd go in her room and turn on the music and rub her back (sometimes change her diaper) and kiss her and tell her I love her and goodnight real quietly and after a couple mins she'd go to sleep. :D
Good luck