The Pyranees are great. Andorra is a blink of an eye. I was there in 2012 and they had checkpoints set up at the borders, but I found out that this is not always the case.
If you get down into wine country, there are some cool places like Chateauneuf de Pape, especially if you like wine. Carcasonne is a fun town with a big castle to investigate. The castle is kinda tourist-y, though, but still fun.
If you get into Spain, you MUST get to Vielha. It's mandatory.