The route you are proposing, going through West Virginia and Kentucky, is a perfectly good alternative to the route I outlined above. It is only about 50 miles longer and can still be done in two days of good, steady driving with an overnight around Lexington KY. That is important. Charleston WV is not far enough to get on your first day, That would leave you 750 miles to drive on the second day. That is far too far to be safe. If you plan to do the drive from Washington to Kansas City in two days, you need to split it as evenly as you can between the two days. Your routing leaves a little less 'wiggle room' for scheduling your overnight but would perhaps be a bit more scenic. Also, I-64 carries considerably less traffic than I-70 and so would be a bit less stressful at least as far as St. Louis.

AZBuck