Another thing we have done is gotten webcams so we can Skype every night I'm away. Skype is free all you need is a webcam and you make video calls over the internet.
I'm working on putting photos of Lizzy and I in her toy photo album. Lizzy has always enjoyed looking at photos of our family so we have a couple toy photo albums with photos in it for Lizzy to look at.
I got Lizzy a gift to open the night I leave. It's a bumble bee pillow pet with a message "Mommy will bee home soon. I love you. See you soon." I figure she can cuddle with it and sleep with it while I'm away.
So far that's all I have planned but I hope to include her in packing and explain to her that I'm leaving for a few days but will be back. Thankfully, my job doesn't require a lot of travel because I'm a wreak thinking about leaving Lizzy for a few days. If you have any tips please comment!