Hi it depends what type of thing you are looking for. I stayed in aix 2 nights and antibes 2 nights, then nice for last 2 nights of a 23 night trip.. Aix was great to see Cezanne’s studio and the fun library entrance with giant books outside, but there was a LOT of construction going on near the main round about by the TI and all the bus stops. It was VERY hot July 3-5 of course. I thought the market at Antibes, and in Nice even, were just as nice if not better than the one in Aix, although they were all amazing! I’d forego the extra transit time of getting to AIX, since you are alr doing that 8 hour tour, and stroll through Antibes. Without a doubt, Antibes! They have an “old city” area, fortress, marina, SANDY beaches, and plenty of shops and cafes. It’s very manageable. I heard many people say they would not recommend Marsailles for people with limited time or have other places on their lists.
DO go to the Antibes market (daily except Monday’s? Closes by 1). Picasso really isn’t my cup of tea, but the Grimaldi Mansion that houses his museum is the real treat, with its vast ocean views from inside and on the terrace, as well as over the Spanish style rooftops. Stunning! With a lovely church next door, and around the bend from the market and cafes. There’s lovely walks around the ramparts, and a small boardwalk (sidewalk) along the beaches further west of the city (Plage Solis, i think?). It was across from our place, Hotel Josse.
We did an 8 hour van tour into villages from Avignon and enjoyed it. Can you just go directly to the tour operator instead of through Viator? It is usually less expensive. The trip sounds great. Maybe you can spend the time in Grasse writing in your journal or catching your breath while the others tour the factory. And, have you already been EAST of Nice? Mom and I took a bus for 1.50 Euro to Monte Carlo, and did a little train tour there, as well as visited the casino area and the Paris Cafe for a nice dinner before heading back to Nice. 3 Euro round trip! Plenty of other stops along the way looked amazing if you get an early start. Rick’s Provence book has great tips. Anyway, Bon Voyage and keep us posted!