So I went and did it. I removed the spiky bamboo stick vases, plugged all the electric sockets, and put up those safety gates.
When I went to install the no-hardware, no tools, easy peezy gate, it would absolutely not fit in the door frame. I realize that this is most likely the fault of the 50 year old house and not the safety gate, but I'm guessing there are plenty of other houses that are having the same problem.
Then, it's a whole other ballgame trying to get the gate open. It claims to hold its place so that you don't have to constantly re-adjust the panels, but I can't seem to figure that part out.
So here's our not so perfect, but gets the job done, off kilter gate. It's pretty much on a diagonal to fit the frame, but it's probably better than nothing :)