St-Paul is actually no farther from surrounding sights than is Mougins. It takes only about 15 minutes to get down to the coast, but it's also a short drive up to Vence and Tourrettes-sur-Loup.

From Mougins you can go up to Grasse and the very nice small town of Valbonne and down to Biot and Vallauris. Cannes, of course is just a short jaunt south from Mougins.

If Voile d'Or is fully booked and you still want Cap Ferrat, the Brise Marine is right up the street. It's not as luxurious but the view is beautiful. FWIW we stayed a year ago in Les Romarins, Gordes, Le Hameau, St. Paul de Vence, Chateau des Alpilles in St. Remy. The advice you get here is excellent.

On locations, all you have to do is look at a map! If you stay in St. Paul, you're right there for dining at La Colombe D'or. Vence is a market town (you said you wanted to visit a market) just up the road. But St. Paul is further from Eze, Nice airport, Hotel du Cap and Villa Ephrussi than if you stayed in Beaulieu, Villefranche or Cap Ferrat. But as Underhill says, Mougins is probably even further. (Based on what you said you want to do, Mougins doesn't make much sense to me).

If you want to go to lunch in Eze on arrival, it's a good idea but I wouldn't go all the way to St. Paul (or Mougins) to check in and then go back. A visit to Villa Ephrussi can be combined with a meal at Hotel du Cap. Since the places in St. Paul are more affordable, that's what I'd do.

We had a 8:00am flight out of Nice airport. Staying in St. Paul de Vence made for a very easy half-hour drive at 5:30am. The airport is west of Nice so driving from St. Paul you do not drive across Nice.

Thank you everyone! I have finally looked at a better map and see the exact locations of each town. We are now steering away from St. Paul and looking back west...