Alejandro Orfila, secretary general of the Organization of American States, began his diplomatic career as a courier. It was "nothing but traveling. Today I do not enjoy travel so much. I prefer to be there, but to reach the destination--that's the problem! Going through Customs, ticket lines, facing plane delays."

But Ambassador Orfila, whose second term at the OAS will end in 1985 (rules do not permit re-election to a third term), still travels when not spending "every weekend that I can" with his wife, Helga, at their 200-acre estate in Middleburg, Va., where they enjoy horseback riding. They own 12 horses.

Recently the secretary general made a business trip to Atlanta to give a speech. "I had the pleasure of seeing many of the old families of Atlanta in their homes and visiting their farms. That in itself was a vacation." A Manhattan apartment is used "about once a month" on business trips to New York. "At least a third of my time is spent in Latin America."

"I would prefer to go to different places each year," Orfila says, and his choice of favorites depends upon "what is the mood."

* The Grenadines in the Eastern Caribbean from Antigua to Grenada: "I don't think there's anything more impacting if you want to enjoy the sea, sun and sand. You rent a boat in Antigua or St. Lucia and you go island hopping."

* The desert: "I come from the desert of Argentina. I like desert vacations. It's a different kind of thing, isolated. You have a horse and go out in the desert . . . it gives you an opportunity to be with yourself, a wonderful way to get a better picture of yourself."

* Developed countries: "Suppose you want to amuse yourself. The best area would be the Mediterranean, from Marbella, Spain, to Greece. Sophisticated to ancient, from very big to very small."

* Jamaica (where they own a large home): "I don't go more than once a year. My wife goes more often."

* Jerez in Spain: "My only hobby is horses. Often I tie in my vacation or visit with areas having to do with horses. Jerez produces two things I'm connected with--Andalusian horses, and wine, which is my family business."