Keep in mind that you can definitely have a 2-week vacation and head West from Michigan. We've done it many times when the kids were younger and they still talk of the trips. You just have to pick one or two places to visit that are close to each other and not try to see the whole West in one trip.
A highlight that they still talk about 40 years later is the horseback ride early morning and having the cowboys ready to serve a hearty breakfast out in the boonies in Yellowstone and the one kids' horse farting all the time.
Another one was getting snowed out (we were in a tent) in Rocky Mtn. Nat'l Park and the forecast didn't look good so we did a very unplanned thing and drove to Mesa Verde Nat'l Park. They absolutely loved the ranger-led tours of the ruins and climbing the ladders and scooting through a tunnel to get to them.
Yet another was just the fact that we rented a small Class C and they had the cabover bed as their little private space for the two weeks.
Kids enjoy simple things!
You can also cruise if you only have 2 weeks including driving time to get there. There are many short cruises.
