route suggestions - central Indiana to Washington DC
We are planning to drive to Washington DC for spring break with our kids this year. Most of our trips with our motorhome have been relatively short drives (4-6 hrs) on the flat highways in the midwest. I've looked at the maps a few times trying to pick the "flattest" route to DC for us. We will be going out I-70, but have a choice to make when we get to PA and I'm looking for recommendations.
Would I-79 south to I-68 and across to I-70 be an easier/flatter drive than taking I-70/I-76/Penn Turnpike all the way out?
Thanks in advance,