Lawrence, Kansas, is a pretty college town on your way East. There is an annual ride there called the "Octoginta" and the local bike club posts the route map for each year's Octoginta on their website (or you can find it on MapMyRide or Bikely.com).

Typically the route goes Southwest of Lawrence and routes around Lone Star Lake and Clinton Reservoir, or it heads up north of town. There would be nice camping at Lone Star or Clinton.

You could spend another day in that area taking loops up toward Perry Reservoir.

Another nice ride not far off of I-70 would be to stop in the little town of Lindsborg, Kansas "Little Sweden USA." Good pie. You can take some backroads toward the west of town toward Kanopolis reservoir, and to the little town of Marquette.

And in Missouri there is the Katy trail...