My kids had videos of Daddy reading to them, mixed in with video of him playing with them. They loved that darn DVD, watched it every day and they had to have it on ALL day. If they left the room and I turned it off they got upset. They did awesome, as long as they could hear Daddy's voice. Considering they were 3 & 1 at the time I didn't care.

I heard my husband's voice more that deployment than any other time. lol Sadly, they wore it out but the day it stopped working was the day that a DVD came in the mail. My husband had the opportunity to record himself reading a book (it was some program) and they sent it home. Perfect timing!
We've also have the Build a Bear workshop animals. My husband went in with them, they chose the animal together and then he recorded a bedtime message. They've had those through two deployments and even though my son is 9, he still plays it when his dad is gone.
I always would tell my kids that daddy has to work to help other people, that he misses them and loves them so much. Being around family and hopefully making new friends will help her get through the deployment. Hopefully he can call/skype often!