Field trip, usually by a group of people who attend something together - students in the same class, workers in the same enterprise, even teachers in the same school (which is the kind of appology from the budget for all the other shit). The latter didn't happen while I was teaching, though. Wrong school, I'd say. Lazar brought nice slides from Zmaj visiting Greece; someone else's negative from their trip of USSR remained in my archive.
The trip was pretty much what it is today, except that the whole organization of it was done through the then tourist agencies (of which there were just a few) or trade union resorts or whomever. The acommodations were whatever they find - from quasi guest rooms with military mattresses, to high school dorms, to no-stars hotel rooms with a bathroom per 4-5 rooms or per floor. There were even tents, but they stopped that just when it was my generation's turn.