The single piece of advice I have is this:
- Always talk well of their daddy, and there won't be hardly any distance between them at all.
My dad was deployed at least 6months a year chasing Russians. This was ages before I could IM friends quite literally in foxholes, or skype with friends on the frontline. When the boat (submarine, so boat is the appropriate word) surfaced sometimes mail got out, sometimes it didn't. We always got calls from ports (infrequent), on phone lines so ancient that one had to shout to be heard, and that was without the cacophony in the background. Only my mum got to talk, but we weren't the worse for it. He DID always bring us each a trinket home :) :) :) Yay! Presents!!
But my mum was always happy with our dad, because for US daddy was never really gone. No tearful goodbyes, no mum ranting about dad not being there... just "Your daddy would LOVE that picture" or "Your daddy LOVES seeing you girls jump in leaves/ dress up/ be so polite/ etc."
Every day our daddy was in our lives through our mother... and he was always cast in the best light. Yes she got upset, I know as an adult, but for US... daddy was a shining light and always in the room so to speak. When we'd "miss" him, she'd tell us about what he was doing... or have us write him a letter or draw him a picture or tell us a story about him. So he was never, really, ever gone.
I'm sure there were times we cried, but I don't remember. What I do remember is how much she loved him... and how happy loving him made her... and in return, how much we loved him.
Note: The BIG "farewells" & "welcomes" (the types where a news crew might be... whether it's at a depot, dock, airstrip, or airport) are really pretty traumatic to kids, and generally should be avoided at all costs. If you want to go, by all means... but it's like anti-disneyland or 5am christmas sales with tons of pushing/grabbing people) for kids (even the welcome homes). Overstimulating, scary, and VERY overemotional. Babies can generally handle it, but even adults have a very hard time. In a word : Babysitter.