thepla;

My trip took 2 different routes. Going I went AA to Madrid, then drove to Algercias and took the ferry over to Gibraltar. Spain had the highway border blocked at that time requiring the nautical experience. Returning was much simpler as I took BA from Gib to London, then AA non stop back into DFW, which was a breeze. But maybe connection times are not favorable now based on your post, or maybe the service is disc.

Either one of these examples would earn miles, but of course the AA/BA is more favorable.

Good luck. Enjoy the Rock. If its your first trip, take the trolley to the top. A nice short side trip is Tangiers or Ceuta on the hydroplane ferry.

Good luck.