I flew to Portugal last year stopping in Valladollid and San Sebastien en-route.

No particular problems. Airways and en-route airspace all seems to be Class E below 10000′ so VFR at Semi-circular + 500′ is the norm.

Needed prior authorisation for a permit aircraft. PM me if you need contact details.

Most of the larger airfields have standard price structures, but landing fees never more than about 10 Euros and reasonable Avgas price too.
I did suspect the refuellers of copying the CC details as I had a fraudulent transaction from that part of Spain a while later – so be careful.

Some big hills around, so pick a sensible route if your not happy with mountain flying.