for you and Mr C - clothes that can be interchanged, like pants that go with 3 or 4 different tops

for the kids, I'd go with what Snowy Love is saying for the weight of the clothes and throw in some babylegs - the kids can have them on their arms and legs if need be.

Just pick things that will dry easily - so not too much weight in them, just layer them on you all. Jeans are a killer for washing and drying (unless you've got access to washing machines and dryers)