Calais to San Sebastion

Hi, I'm driving from Calais (where the ferry drops us from England) down to San Sebastion and then on to Pamplona. i have about 4 or 5 days to make the drive as I am leaving on the 1st of July and want to spend a couple of days in San sebastion before going to the running of the bulls.
Does anyone have any suggestions on where to go on this drive? I'm not interested in going to Paris and at this stage looking to probably stay coastal if possible. Im in to all things outdoors and might even look to have a surf at some stage along the drive, I also heard that there is a good castle in this region somewhere and possibly the normandy d-day beaches?? does anyone have any suggestions? Thanks