Hi!
We did a private tour from Villefranche when sailing on board the Splendour of the Seas last year. We went to Nice, Eze, Monaco and Monte Carlo in 5 hours. I believe Cannes is further, so you might need more time...
Villefranche is quite small. You should really take a tour to see the French Riviera. It is beautiful!
We paid $85 per hour for a comfortable minivan (capacity 8) with an English Speaking guide. We made our reservation on line at
www.portsidetours.com - A friend of mine booked many tours with them this year an got a discount for her children. You might want to check with them...
Good luck!
Louise