I have a first-person response to this reasonable question about mechanics of life in the near past, but since it is first-person, I will delete it if the mods object - so apologies at the outset.

I typed thousands of pages on a relatively small Royal typewriter until I snapped the "s" off its arm in 1978 (after using it to compose my first publication). It would have been regarded as portable among typewriters, but I would never have dreamed of taking it anywhere. It was still too big to just carry around. I'm sure reporters moved their typewriters to their hotel rooms, etc., but one didn't just pull one out of one's bag like one does with a laptop or pad and have at it. And you're right, the noise would have been really annoying. I never saw anyone do that. Typing in an apartment was, however, fair game. And a private railcar was just that - so it was also fair game. Apartment life has always presented a range of noise-related problems. That never changes.

edit: I broke my typewriter's "s" in 1978, not 1977 as originally posted. One must keep one's "S's" straight. And while I might have lasted a while without a "Z", without an "s", I had to find a new typewriter quickly. The replacement was a remarkable tool. It was - get this - electric! And although it was far less portable than my old broken Royal (which I still have), I took it to campus in 1981 for my graduate written exams. I was the first graduate student to do this; the department later allowed graduate students to use department typewriters. I typed 45 pages in 9 hours of exams (in three fields), and by virtue of typing rather than writing, my readers could actually read what I wrote. Which could have been a disadvantage.