Stu - rough plan, could these dates work?
I would depart Sun 25th Sept, arrive Santander 26th.
Meet up at Zaragoza area and camp night of 26th.
Drive down to Guardamar, camp for 2 nights if poss as inlaws live there, beach is meant to be good and undeveloped.
Arrive Tabernas around 29th.
Maybe 3 days lanes?
Thats up to about 2nd October.
I would then head north aiming for Caen, get back to Uk about 7th Oct.
Out of all that, the only important date is the 26th to tie in with ferry arrival, how does that fit with you?
Pete