skooz:Our friends hosted a going away party before my husband left because he wouldn't be back before we PCSed. We kind of just considered it a going away party for both of us and didn't have another get together when I left a couple months later.
I would probably do something like this. One party as a combined good luck/goodbye party. Then for you and your son I would have a very close dinner party or something with only close family and best friend before you left.