Yes, and I think the very best solution is not to get her another pet. It sounds harsh, but you are quite right about small excitable dogs tripping her up, and larger ones need too much exercise, even those who are older. Then there is the issue of how long she will live, versus the dog and it's not fair, especially to a rehomed dog, to find its owner gone yet again.
You need to find something to fill that gap which is not a large live-in animal. Think bird or similar. Something she can easily care for and talk to, keep clean and which will not outlive her by years. See if you can somehow bend her a little bit to give that a try.