Car trip

St, Remy is close to Les Baux and would be a good one night stop before heading to Beaune, then you would have a more leisurely drive with the possibility of sightseeing a long the way, and 2 nights in Beaune. I have done the Burgundy to Loire drive in the reverse and it is also a long drive. Both of those drives will take a full day. I'm wondering if you would do better going directly from Provence to the Loire, then Chartres and Reims, as you make your way to Paris, as I assume that is where you are headed. Or you could go from the Loire up through Normandy.

I wonder what time of year this trip would occur.

I'm sure Orleans is a nice place to visit, but since you are coming from the south, I would ask why you aren't staying closer to the most popular and worthwhile Chateaux? Indeed, you have to decide whether you prefer those to the west, or the perhaps even more famous ones to the east, of Tours. (You clearly plan to drive farther north, but you could return the car in Tours/St. Pierre des Corps and TGV to Paris if that's your last stop.) Only because you mentioned abbeys, I would remind you of the UNESCO WHS Fontevraud, quite far to the west.

I don't see Avignon and Loire chateaux as the same trip, I mean requiring a "choice" between. There's plenty of French and Roman history around Avignon, and a summer Festival if you are lucky/unlucky enough. It all depends on what you want to do. Did the people who went to Avignon go to the Pont du Gard or Orange?

As another noted, the time of year affects this trip a lot. We would have liked to see some exterior "Illuminations", but it did not fit our schedules. There's also crowding and no-air-conditioning to consider.

We are doing this part of a larger trip first week in October'18. We have two other couples joining us for two weeks. First week is in Antibes. Then we are working our way to Paris. I really wanted to show them les Beaux art caves. Which is why that's our starting point.
My husband and I have already been to Normandy and two nights in Bourges earlier this trip, which is why we aren't going that direction west. I had originally wanted to do Beaune and Dijon, but when I realized how much time we'd spend on the car am looking to see if other routes north as scenic, but maybe less driving.
Avigion area is not where we want to focus as we transition to Paris.

Going to the Loire Valley from Les Baux is a lot more driving than going via Burgundy, so I’m a bit confused byyour post. You have to get around or over the Massive Central mountains somehow. If you are looking for a smaller place to stay in the Côtes du Rhone wine region, try Seguret, on the most beautiful villages list. Vaison la Romaine is a little larger, a town.

Could you clarify what you mean by driving, the Loire and Burgundy.

We have 6 nights in our travel. We visit Les Baux the first day. We are planning our route back to Paris, knowing we want time in the Loire Valley 3 nights. Probably staying between Tours and Orleans. Trying to decide what route to take from Les Baux to Paris. we would break up 6 nights, maybe one night, then two nights and 3 nights.

So the Loire is for sure. Viamichelin.com shows three routes, the ones I mentioned. One goes around on the west and you have Nimes, Clermont Ferrand et Bourges, not well-know for wines, bur a lot of old religious buildings.

What viamichelin calls route 1 goes north along the Rhone to just below Lyon before cutting across the Massif Central to Clermont and on north. I’d stay two nights in Vienne—a former important Roman city, and one in Clermont with its amazing Romanesque religious buildings.
I haven’t checked the map on this, but you could see how far south Le-Puy-en-Velay is out of the way from Clermont and do Vienne 1, Le Puy 1, Clermont 1. You get the Côtes du Rhone vineyards that way. Note the autoroute from the Rhone to Clermont is twisty-turny.

Number 3 goes further north before heading west at Nevers. You go through Côtes du Rhone, the Macon/Beaujolais in Burgundy. The drive goes around the Massif central to the north, a few hills in the Macon area. Again 1 night in Vienne, one near Macon or Cluny or Paray-le-Monial, a night in Vézelay or a return to Bourges. Your only drawback is having to choose between driving the autoroute through Lyon (stuck in traffic jams inside the tunnels) or choosing the autoroute around Lyon. Check maps.com for jams and choose the one that’s moving the best.

Have you been to Sarlat? The area by the Dordogne river is a must, I would love to go again, there are many Chateau's and villages to explore La Roque-Gageac, Domme and more. I would spend more time there than in Paris but we just not big fun of big cities. Have a wonderful trip :)