The Pyrenees are a beautiful mountain range that can be explored in multiple ways.
Taking the car is easiest. But you'll find the most beautiful spots when you go on foot. The remotest parts are often the most beautiful. Many hiking tracks have been set out. Often you'll find one or more starting in every village. In addition to walks of one or several hours, there are also multi-day hikes.
The Ariège is a relatively unknown area and therefore still incredibly unspoilt. There is no mass tourism here, so you can fully enjoy the beauty of nature.
Between the Mediterranean Sea and the Ariège, in the Languedoc, you'll also find a part of the Pyrenees that is worth a visit. Climb the Canigou or meander through the valleys. A great experience!
In all cases: go well prepared and decide on your route beforehand. Getting lost can be a nasty experience.