Never been the I-40 I-75 route but the one up I-40, 74, 77, 64, is a good ride and a pretty drive in the summer when everything is green. Several places in WV you can pull in and over night.
I-40 to 74 in Winston Salem to 77 to 64 in Charleston WV. You have a more hilly route with this one and 2 generous tunnels and a toll road through WV. The easier route is I-40 to I-75. Use the Good Sam trip planner to find an overnight place to stay.