Thanks for you help.
You gave me EXACTLY what I wanted and needed to know. I've already been to Memphis (flew in for a day to see Gracelands then flew out). It isn't a major stop, my girlfriend just wanted to see it if it was on the way.
Unfortunatly I can't do the trip back to the other side as we are going north and stopping off at Washington DC, NYC and then to Canada to go boarding and see Niagra Falls.
We actually wanna see a fair bit on the east coast, as mentioned places like Grand Canyon, San Fran, Vegas and also head into Tijuana for a day, it's been about 12 years since I've been in Mexico... cheap Corona's!! Back in 2008 we caught buses, but didn't visit as many places, so would bus be the way to go or would driving be better? The let down with the bus was we couldn't stay as long at SFMM and Knott's at night.