I live near Memphis and have made the drive from Memphis to Knoxville many times. I think stopping in Memphis is a good idea. It is as least an 8 hour drive from Knoxville to there. Memphis to Little Rock is a little over 2 hours more. There is a lot of constuction going on around the Interstate in Memphis, and there has been construction on the Interstate just across the river in West Memphis, AR forever! I would not suggest that anyone who is unfamiliar with the area try doing it after dark, much less when fatigued! I would suggest a hotel on the east side of town, before you get on I-240 that loops around the city. There are several good hotels on Germantown Parkway near the Wolf Chase Galleria. There are also many good places to eat. Hope your father has a nice trip!