Dora and the Monkey would tie together guys. Dora's best friend on the show is a Monkey named "Boots". Here is a backpack I found on ToysRus:
http://www.toysrus.com/product/index.jsp?productId=2886471
In George's interview he is pretty specific about it being a WHITE backpack with monkeyS on it and makes mention of it probably coming from target. I think there were two backpacks. Cindy found the Dora one in the car. However, In cindy's interview "a friend of Caseys (she can't remember his name....maybe chris)...brought over a bag of some stuff of Caylee's that was left at his house....I have yet to here what was in that bag...maybe another backpack? George reported that Caylee had many backpacks.