Roadtrip planning!

Well this summer my aunt and me are planning on going on a roadtrip and I have to come up with places that we should go to! We want to end up at a beach and are headed west towards Oregon. So if anyone could give places that are kool places to visit between Oregon and Iowa that would be awesome. I want to go through Montana and I want to go to a lot of parks. I'm pretty sure that she said the trip was only going to last about a week for the to Oregon part....so that limits what we can do. I'm a history freak so museums are always interesting but I would prefer outdoor places to stop at. I've never been on a Roadtrip before so I could really use some help please!