Hi Helen,
I will be driving to casares del sol this Sunday (first time). Bit of an adventure. I will be using the channel tunnel as I have a dog travelling with me. We will be doing two stop overs to break the journey up, nearly 22 hours from calais to casares so I've been told! I will be using toll roads as this will be the fastest route. There are a few good route planners on line that help you plan the route, show where the tolls are and give an approximate cost of the journey. There are also some good You tube videos of different routes to Spain.
My UK insurance covers upto 90 days in Europe. Check with your UK insurance provider for details.
Hope this helps.
Best wishes
Julie