Single mom and going away for a week. Tips for helping a just-turned-3 y/o through it?

I'm going to have to travel for a week near the end of the January. I'm a single mom to a child who just turned 3 years old at the beginning of December. Two close friends of mine will be taking care of her in our home so she's in her own environment. She will still go to preschool and mostly have a normal schedule other than mom not being here. Other than an odd night or two spent with her aunt, we haven't been apart and I really want to make sure this isn't traumatic.For those of you that travel from your small kids - what do you do to make them most comfortable?I was thinking of Video chats - but I've also read that may make them wound up and upset? What is your experience?She did really, really well with the advent calendar this year - she has one where she put a magnetic ornament on a tree and one she opened up with chocolate. I was thinking of making a calendar with stickers on it so she would know when mommy was coming home. Also thinking of leaving 7 envelopes taped to the wall with notes, pictures and a little goodie.My daughter is very bright, very verbal but is on the clingy side. She's been going to a new preschool since September and we are just NOW getting to the point where drop off isn't a dramatic point of her day and she isn't asking for her momma every 15 minutes throughout the day.Any advice or insight is appreciated! via /r/Parenting http://ift.tt/2iq2o1M