I've flown light aircraft several times the route you are taking from south of France to Morocco, but always IFR.
Don't go to main airports like Barcelona and Valencia unless you really enjoy paying huge handling fees and waiting for mandatory transfer buses etc.
Sabadell is the GA airfield for Barcelona. Good facilities, you can just walk to your plane, but very expensive fuel.
Zaragoza is good and relaxed for GA.
Jerez is OK. Almeria and Alicante reasonable. But all of them insist you wait for transfer buses and you can't just walk out to your plane.
Morocco is very easy, controllers very good (better than Spain), fairly bureaucratic but just be like the moroccans and smile, keep your humour, be patient and you will have a very nice time with them. Just don't expect them to live life at the same speed that we are used to!!