Cell phone. I carry earphones and a music source, but no gas mask or O2 supply.

As to the OPs questions. Luckily I never sat in the smoking section, but it really didn't matter, all the planes stunk back then whereever you were sitting. The smoke was just fresher in the smoking section. Keep in mind that there were usually a smoking section in each class, so if you were in the front of coach, you were right next to the FC smoking section. I know I flew TWA and National, and don't remember specifically which other airlines, and I don't recall having any kind of curtain separating the smoking section. I do remember the "dividers" that were little plastic signs that were attached to a seatback. I think they could be moved to quickly adjust the size of the smoking section if needed. I also remember that my parents (and others in non-smoking) would walk back there for smoke breaks, so the aisle was usually full of smokers too. Sorry I don't have any Continental specific info, but I don't think it varied much by airline.

As far as domestic vs. international, smoking was banned first on shorter flights (under 2 hours, I think), then longer, then all domestic. But prior to that, all flights of any duration allowed it.