I remember the time thing, but retired 3 years ago.
To see lots of wildlife I agree with some of the others, either Yellowstone or the Black Hills with Custer State Park. You will have a hard drive, but with school aged in the family you are probably young enough to do it. Just be careful, and remember they fine truck drivers for doing this. Avoid the Sturgis area when the bikers are in town, unless that is the reason for your tip. They take up all the hotel rooms and camping spots for quit a ways around.
A good way to see Yellowstone is to stay in Gardner Mt. You can pick up Momma in Billings, Mt. on the way. I think you can still get flights to Billings. At least 2 campgrounds open in Gardner in 2011. One is maybe 5 minutes to the park gate. Then you can just drive and hike all day. We enjoyed it, but we stayed over a week. Do not miss the Tetons. If you are Catholic go to Mass at the little log church in Teton park. We got a Bishop for a Saturday Mass on his vacation. Really neat in a small crowd. Never met a Bishop while wearing my shot pants and ball cap (outside) before. Nice guy, from Chicago.
I hope you have enough time ahead to get more than one bucket list trip. Good luck and a safe journey.