[GCS]

For our then 3 year old boy we had great luck with a bag of teddy grahams (resealable so we could just bring them with us every day!). Dont forget a sippy cup and a bottle of water.
He liked the stuffed animals but those were less interesting to him than the cars. Especially a car that made noise. We brought books with real photos not illustrations in them. That was a big hit. We brought clothes and shoes to check for sizes and then to leave with the orphanage.
I also brought with the developmental pages from The Toddler Years book from the Girlfriends Guides series. I figured he'd be delayed but I could reference where he should be and where he really was. This was a big help!
Leave a disposable camera and they may take pictures for you during your time away.
Take lots of pictures. I wish we had video taped things but we really couldn't manage that with the camera and both kiddos so we opted not to. I would love to have that footage now.
We also took a tape measure and got all new measurements for our IA dr.

Good luck and have a great trip!