instead of Saint Remy for our base to explore Provence..can you recommend a wonderful hotel? Two adults late September early October. Mid-range $$$ or even more if fantastic! This town sounds perfect we will have a rental car.
What made you discard St Rémy? Isle sur la Sorgue is very nice, but in my opinion choice between the two should be dictated by the sights you want to visit while in the region. Isle sur la Sorgue is more convenient to Lubéron, St Rémy to Arles, Nîmes, Pont du Gard. Avignon is good from both
Can't recommend a hotel in Isle sur la Sorgue but I will also point out that hotel choice is much larger in and near St Rémy.
We stayed at the Grand Hôtel Henri in June 2019. Great hotel - good location and spacious, very comfortable rooms. We would return in a heartbeat. In Saint Remy we stayed at Hôtel de L'Image which is definitely quite run down. Carpets in the corridors were stained, walls needed repainting in the worst of ways and the grounds, while once grand, were overgrown and the water features full of algae. Our room was so tiny we had no where to put our suitcases. It was the simple things that made us crazy - no shampoo or towels and no hangers in the closets. Staff was happy to provide them but we didn't feel we should have had to ask. Not a hotel we could recommend.
ISLS was awesome. I would definitely choose it over St Remy too (its an oasis in what is otherwise very dry Provence; and a great base for exploring the Luberon or Avignon).
Consider staying in a villa outside of town, so you can get a pool. We stayed in one called "La Morgate de Provence" but it seems to be hard to find on Google now (maybe out of business). Try AirBnB or VRBO or "gites en france" website.
My husband and I drove around St. Remy and discovered a beautiful old estate that someone has bought and is booking the rooms. It is wonderful. Look up Le Chateau des Alpilles. We had lunch in its gardens 2 years ago in May and it was delightful....juts what you would picture in your mind of a lovely estate in southern France. They have gardens and a pool......we sat and read outside by the pool for hours one afternoon.