A little different twist but less interstate. Some place after you get to Kansas, turn west on one of the back roads that runs straight west something like Hwy 36. Stay working your way mainly west until hwy 83 which will take you north to North Platte, NE. From there work your way up to Ft Robinson State Park and spend a night or two. One thing you must do is take the stage coach ride at Ft Robinson to really appreciate how they traveled in the old west. From there it's a nice easy 1/2 day jaunt up to Custer. If you are pressed for time, you could skip the back roads of Kansas and stay on the interstates up to Lincoln, NE to catch I80 over to North Platte.
Most of the roads like 36 and 83 are smoother than our east coast interstates with a lot less traffic. If you do find yourself on a rough section, just catch the next road to the north, follow it for awhile than turn back north. You can either make good time by just taking the road which usually has a bypass around most towns or slow down and explore.