PJ,
I am here in Memphis and as long as you know that Graceland was kind of preserved after Elvis died, it looks like you are stuck in the late 60's. You can go thru it in a few hours, unless you want to go thru his planes, maybe another hour. Not much else here in Memphis unless you go to Beale Street, or Tunica, MS has casinos. Good place to lose some $.
It is about a 3 hour drive toward Nashville to JD distillery, and like Ty said, you will not get a drop to drink.
Unless you are a big Elvis fan, I would say go to DC. And why drive back to Indiana? Just leave from DC.
If you do make it to Memphis, give me a heads up. Maybe we can do lunch? Best BBQ in the US.