There is a chance that they will have a great time while you're away, and all your worrying will be for nothing.
We lived in a remote area and both parents used to go away from time to time. We LOVED it, even though saying goodbye often involved some tears. I don't know if both were aware, but we would always get some kind of treat after the airport dropoff. It was probably the only times we had takeaway or junk food. We also got to go on lots of sleepovers to friends places, which also invovled food that was banned at home.
As we got older, the only downside of mum going away was getting to school and realising we weren't dressed properly or we'd forgotten to brush our hair. I think I wore my slippers to school one day. Another day I had my pjyama bottoms on under my uniform -- some boy took great delight in pointing this out when I turned upside down on the jungle gym. Dad never noticed these things but unfortunately our teachers did. My sister had a note sent home once telling Dad to make sure we brushed our hair before we left home. Hehehe. Dad used so many bobby pins on us after that note.

So once you are away, try to enjoy your amazing experience rather than worrying about what your darling babies are doing.