J.
How about creating a family journal, your daughters can help you with it. Everyone can write down what's going on, what's coming up, what their excited for and what they could use some help/support with.
Maybe you could do more of a personal journal that you could share with him that included the struggles as well as high points to your day.
When my husband traveled a lot, we gave each other notes (not full length letters) just to let one another know we were thinking of them and looking forward to being together again.
Good luck.