Pisa to Naples Road Trip, taking in Tuscany and Amalfi Coast

Hi Elena
We are considering flying from the UK next June (2016) to Pisa for 2-3 weeks, we wanted to have a number of days staying and exploring Tuscany and also drive down visiting the Amalfi coast, arriving in Naples to fly home to the UK.
Do you have any suggestions for routes or places to stay and typically how low is required in the different areas.
We visited Venice earlier this year and spent 5 days there, anything less and I would have felt cheated that we hadn’t seen it all.
Kind Regards
Corinne.