The "all-American tour of Southern France"?! I was never remotely even aiming at that....
At any rate, I decided to skip France all together. From everything I've read traffic is bad and there is a lot of info that I just don't have the energy to want interpret.....
So, we are flying from Sofia to Milan on 23 August, taking a train to Florence immediately after arriving at Malpensa; we'll spend 2 nights in Florence (23 and 24), then off to Pisa, Cinque Terre/Portofino/Portovenere for two nights (25 and 26) back to Milan for 1 night (27) and then back to Sofia--our flight is in the morning of the 28th.
All that in 6 days, given that the flight from Sofia to Milan leaves early and is relatively short.
Does it look doable? Any suggestions on how long we need to see Pisa, CT, and the two ports?