Saville to Tangier

By land and ferry, you'll use up the better part of 2 days just getting to Tangier. The best 2 cities for a short visit are Fes and Marrakech. They aren't very close to each other nor to Tangier. Best would be to fly from Spain to one or the other and do a day trip or two. Or fly into one, fly to the other and then back to Spain.

However there is so much to see in Andalucia, I suggest you spend all your time there. Then plan a separate trip to Morocco which is a terrific destination for a 2-week trip - and you still wouldn't want to go to Tangier.

Chani's advice above is spot-on.

Most people who are contemplating a "quickie" side-trip to Morocco from Spain usually are short-changing themselves. Morocco deserves more than a day trip, more than a couple days. And the good stuff is not in the towns along the north coast, it's inland, in the great old cities of Marrakech and Fes (among others). Skip the ferry, it's a waste of time and money. If you want to visit Morocco (and it's well worth a visit), then do it right: skip the tourist-trap cities on the north coast, and fly to Marrakech or Fes (it's dirt cheap), and stay long enough to see some of this fascinating country, and do it justice.

If you have soooo many days in Spain that you have just run out of worthwhile things to do and see (hard to imagine), then fly to Morocco for a trip longer than a couple days. But most people could make much better use of a few extra days by allocating them to Spain, and save Morocco for another trip when you can see the good parts.