For page layout, sketching is certainly a valid option. People don't tend to actually 'set type' that way as it'd simply be too tedious and not nearly as accurate. Instead they 'box out' the layout and 'greek' the type typically as simply boxes or lines of type.
Even in the Mad Men era hand drawn comps were rarely fully fleshed out with completely type. The headlines and key text would be hand lettered, but much of the copy would still be greeked to be spec'd later for the typesetting department to create (either in metal type or, later, photo and rub-down type).
To answer your specific question:
is pen and paper a good way to plan?
Yes. To a point. The benefit of pen and paper is that it's fast. It lets you explore a lot of ideas really fast without getting bogged down with your tools.
If you happen to be extremely talented and hand lettering, then by all means, go for it. But if that's not your strength (and to be fair, it's not a strength a lot of us have), then it's likely just going to slow you down to do that level of detail by hand.