Andorra, a small principality between France and Spain, is said to have 83,000 residents and 10 million visitors per year. A lot of the visitor traffic relates to skiing. In October, however, the main activity is hiking (and may be shopping). There are many trails; a search for Andorra on Wikiloc provides a list of trails each with a description including a GPS location with track and pictures. I used this resource before we left as I realised we would have but two days so it was important to make the best use of our time.
We took two hikes in Andorra, the first was to Refugi de Coma Pedrosa; the second was to Refugi Fontverd in Madriu Valley.