I would definitely ask the in-laws to check up on her. She will love the company and if they can take her out for a good walk, it will give her exercise as well. Being a puppy, the activity will help her expend some of energy.
It sounds as though you are doing everything you can to make sure she will be okay. Having kibble available for her is important as she will eat when she gets hungry. If she doesn't eat too much the first few days, just keep an eye on her. She may not as she is used to having you around but once she realizes that this is going to be the normal routine, she will adjust and settle into it.
You may want to leave a radio on so she can have some noise distraction going on. I was a nervous wreck when I went back to work. Fortunately it was only 5 mins away and I was able to come home at lunch time.