I originally allotted two days for all of the French Riviera and Provence - Monaco, Nice, Cannes, St. Tropez, Marseille, Aix-en-Provence, Avignon, Orange, and more. Of course, nobody could do all that in just 2 days so I removed Florence, Italy from my itinerary to make time for Provence.
Coming from La Spezia in Italy, I get to Nice around lunchtime and make that my base for the next couple of days. I think one day in Nice (Nov 11) and one day in Monaco (Nov 12) will suffice:
- Day 1 - Nice has the best Chagall museum in the world, the Promenade des Anglais along the beach, boat tours
- Day 2 - Take the 9:00am bus from Nice to Monaco to Menton (1 euro for the ticket, good for 74 minutes, so even hop on/off will be cheap). Menton is a locals place with a nice beach and a nice Riviera experience. After lunch take the bus to Monaco. Spend a few hours walking around the main part of Monaco-Ville and then play in the Casino (opens 2pm). It's 10 euros to get into the main casino, but it's free for the "American style" casino next door. Last train from Monaco back to Nice leaves at 11:58pm.
The train from Nice to Arles is 7:25 to 11:50am, with a transfer in Marseille. Much as I'd like to sleep in after getting back after midnight the night before, if I take a later one I'll miss out on a half day in Arles.
- Day 1 - sightseeing in Arles and Les Baux. Arles has a Roman Arena, an Ancient History Museum, and the Forum Square, all Roman historical places. Les Baux is a 30-minute bus ride away and has a great ruined castle (the "dead city").
- Day 2 - Nimes, Pont du Gard, and Uzes. Assuming I'd stay in Arles, take the train to Nimes (8:57-9:24am), a midday bus to Pont du Gard, an afternoon bus to Uzes, and the bus back to Arles in time for dinner. Nimes has the best-preserved arena of the Roman world, the Pantheon-like Maison Carree, the Temple of Diana, and the Old CIty. The Pont du Gard is an incredibly-preserved Roman aqueduct dating back over 2000 years, and Uzes is a less-traveled nice place to relax and recover.
- Day 3 - a full day for Orange and the Cotes du Rhone villages. Orange has more Roman ruins and the Cotes du Rhone villages are in a great wine country. Suggest a wine tour.
There's only one train from Arles to Barcelona, with transfers in Montpellier St-Roch, France and Figueres Vilafant, Spain, leaving at 7:58am and arriving at 2:46pm.