How can I handle taking small kids and myself into a smoke filled house for the holidays?

Quickly. Those who are not used to a smoke filled environment may have a notably rough time when suddenly put into one. There can be an irritation of allergies, asthma, etc. If you or the children have these things, you may need to make other plans. I would prepare them tactfully so they don't loudly exclaim about it, but watch for breathing issues, coughing, etc, and if they happen, make your regrets.
Quickly or don't. Cigarette smoke puts kids at risk for everything from asthma to ear infections - and seeing that you are ok with it may lead them to think its ok. Have the smoker's over to your smoke free house, don't go, or stay 20-30 minutes.