A week in Spain? Or Southern France? Or Paris and surrounding area?

Given the interests that you listed, southern France may be your best choice. The weather is likely to be warmer there, and while I haven't gone hiking in Provence, it seems like a place where you could do that. Definitely has picturesque towns. Paris is wonderful, but if you want to try to fit in some hiking and walking around picturesque towns, that's not your best bet. And as has already been pointed out, the three Spanish cities you mentioned are very far apart.

I will just speak to your first option. There are lots of great places to go in Spain, but the three you list are about as widely spaced, geographically, as they can possibly be. San Sebastian is in the north, Ronda in the south, and Monserrat to the east, by Barcelona. It won't be possible to do all three of those in a week. As much as I love Spain, you would be better off saving it for a separate trip later.

Southern France/Provence would be great for driving, exploring, hiking and enjoying the French countryside and villages as well as a stop or two on the Mediterranean. I would opt for one of the lovely towns (my favorite St, Remy) and simply make day trips from there... it could keep yu busy for weeks.

I've done all three in March, although Spain (warm, but love France more) and Paris (wet, but it's still Paris) were later in the month and based on what you say you want to do, I think Provence would be a good one. We went a few years ago in early/mid March and stayed a week in Arles then 4 nights in Nice. It was rarely warm but usually pleasant and the Mistral wind could make it miserable at times. The markets were all running but some of the smaller towns seemed to close up as soon as the sun set. I thought St. Remy was beautiful but not much open mid March. We went two days as Glanum was closed the 1st attempt. I will definitely go back in season though. Arles was big enough to have plenty to do, but I'm not sure I would have enjoyed it as much 'in season'. Driving was a breeze all over Provence for us and parking was never an issue. Enjoy your trip!

I echo the comments re your ion of Spanish Cities...you need to look at the map to see where they are located. Spain would be doable, but in a different area. As for Nice and Provence you would enjoy the driving in the countryside -not in Nice itself!! Montepellier, on the coast and the small village of Caux, near Penzas (Caux is so small it may not be on the map!) are lovely. The Stone House Inn Bed and Breakfast in Caux is my favorite of all! In Vaison La Romain, stay in one of the ins in the Citie Medieval, on top of the mountain. Be sure to go into the city itself on Market Day, Tuesday I believe, which has been going on several hundred years. Nice has some interesting attractions as well. Beaune would be a good place to visit as well. Lots of vineyards in the area and excellent food choices as well.

If you have never been to Paris then it gets my vote for sure. You could easily spend a wk there and never be bored. It is an experience for every couple. If you still wish to see surrounding area then see Versailles on the rail line. Second place is Provence where you will need a car. You could easily spend a wk in Provence seeing altho the villages and their distinct beauty.. Niceis a fair drive away altho March would be a calm time to be on Fr. Riveria. During peak season it is not advisable to drive on the Fr. Riveria. can't go wrong with either choice. Bon Chance.

I vote for Paris. Paris is my favorite city in the entire world, though, so I am biased. :-) I wouldn't pair Paris with Nice, though. Too much travel time. For day trips from Paris, think Versailles or Chartres - or even Brussels. For the south of France, I'd stay in Aix-en-Provence and visit Nice and Marseille and Tourtour or Gourdon (or any of the entrancing little villages down there) by car. Here's a website to get you started: http://www.francethisway.com/most-beautiful-villages.php And yes, I did say Marseilles. I like it!

From Grenoble it is about a three hour drive to Gordes and the other picturesque perched villages in the Luberon. The area has hiking trails along with great scenery and lovely architecture. Mont Ventoux is nearby. Western Provence has much to see. One time we were there for a week in March. It was cool but pleasant apart from one day when the mistrals blew. We've been fortunate to tour many parts of France. The Luberon is our personal favorite.