Ken Levine has a post about the process of plotting out a M*A*S*H story, which is a very good read for anyone interested in exactly how, mechanically, TV scripts come together. (This is a particularly tricky process for a show that uses multiple stories in every episode, like middle-period M*A*S*H, since the writers and producers must select two or more stories that complement each other, and figure out when the right “beats” should occur for each story in the script.) In particular, the post deals with an important factor in the writing of any show: where you can shoot, and when. In the case of M*A*S*H, which couldn’t go out on location, the only exterior shots they could do were at Fox’s ranch in Malibu, and as Levine explains, they didn’t always have access to that ranch. So they needed to incorporate that restriction into their scripts, limiting the number of exteriors called for, and — later in the season — eliminating exteriors altogether.
And then we had a rather major restriction: We could only shoot outside at the Malibu ranch for one day each episode. So no more than 8 pages (approximately a third of the show). And that was in the summer when there was the most light. By September and October we could devote 6 pages to exteriors. And once Daylight Savings was over that was it for the ranch for the season. All exteriors were shot on the stage. So if we wanted to do a show where the camp is overrun by oxen we better schedule it for very early in the summer. Those 20th guards never let oxen onto the lot without proper ID.
That description of the production process is familiar to anyone who’s read about how old B-movies were made: they were written around the tight shooting restrictions and, in particular, around the sets and locations that they had access to. The TV series is the descendant of the B-movie — literally; that’s where a lot of the B-movie production crews went in the ’50s — and it, too, has traditionally worked the same way. The writers can’t usually demand that some expensive set be built; they can’t even get the kind of access to the studio facilities that a cheap feature film has (like the M*A*S*H movie, which was shot on the Fox lot but at least was able to include more outdoor scenes). They may make use of sets, locations and costumes left over from previous movies, and write their stories around what sets, locations and costumes are available. And it all has to be done fast.
It’s a bit different today, because shows are more expensive to make, have longer shooting schedules, and do more extensive location work. (Also they have access to bad green-screen technology like you see on Parenthood when they want to fake a location.) But it’s still true that a TV episode costs less than most feature films from the same studio, and the writers have to ask, when they’re writing a show, what they can do with the time and money available. And that’s a big unseen influence on the story of any episode.