DC to Yellowstone: how long does it take?

[onlyapassenger]

My boyfriend and I are going to be working at Yellowstone this summer, and we've obviously decided to drive there. We're coming from Boston, MA.

Are there any must-sees in between Boston and Wyoming? Maybe some that aren't so well known? Landscapes? Even sweet cheap motels, or classic truck stop diners?

Anything anyone can remember loving that's in between Boston and Wyoming that's worth checking out?

So far, we're stopping in:
Arlington, VA to see family and sleep/shower
Cedarburg, WI to see family and sleep/shower
Omaha, NE...just because it's Omaha, NE