My recent experience with connections at CDG: I flew Air France IAD-CDG-FLR on June 15, the flight arrived on time at CDG & we had 95 minutes for our connection. Customs and the terminal transfer were excrutiatingly slow, and we missed the connecting flight. We had to wait 6 hours for the next flight that had seats available. And as janisj said, the distance from Rome to Sorrento is not the potential problem -- the driver's exhaustion is.

There is a direct bus from FCO to Salerno, but I don't think it would improve your travel time since you would still have to get from Salerno to Sorrento. It leaves early afternoon so wouldn't work for most people with early flight arrivals.
www.buonotourist.it

<< ...after about 17-20 hours in transit overnight and probably 30 hours awake, driving anywhere is pretty risky... >>

A bit defeatist, in my book...

...ideally, with that much flying time, smart travelers will have spent 50% of those hours <b><u><i>asleep</i></u></b>!

:)

Best wishes,

Rex