We usually stay in condos, but I don't expect they're too different.
Laundry detergent if you're going to wash more than a load or so. Possibly dish detergent or dishwasher detergent as well -- condos usually have a small thing of dish detergent, along with one packet for the washer and a few for the dishwasher; some rental homes are the same, some don't have all three.
Dryer sheets or softener, if you use them. Never been anywhere that had those.
Depending on how much cooking you're going to do (and how much storage you have going out!), you might want to take some old kitchen towels -- often there are only two kitchen towels and a wash cloth, and with my crew we often end up wanting more. If you don't cook as much (or for as many!), may not be an issue.
When I'm particularly organized, I do mixes at home for bars and quick breads and that sort of thing and bring those along. We are not likely to go through even a small bag of flour or sugar on a short trip, and, except for brownies, we're not big on purchased mixes.
I also bring spices in tiny containers, if I'm going to use any, because I don't want to buy a full jar of spice if I'm just going to need a teaspoon of its contents!
We also bring a 9x13" pan, because they don't always have one and I use them constantly for snacky stuff (four teenagers!). I do quick breads that fit in that or in a square pan, since bread pans and muffin tins are rare.
Maybe not pertinent, those last few, since I suspect we do more baking than most people on vacation.

But hopefully some suggestion will get you thinking on things that you'll want for your family.
