You're welcome, Molly!
I've found them to be very helpful.
Here's my experience. They couldn't find my great-uncle in the city directories or in the tombstone transcriptions (it turns out his grave doesn't have a stone).
I went to the library in Toronto which has some Hamilton city directories and I found him through some roundabout way (he was boarding somewhere at first, I think). I followed him forward, then saw the year when his wife was listed as his widow. Then I gathered the names and addresses of Hamilton funeral homes (from the internet) and wrote them all letters. One replied with information!
However, you have the info on Ruth's parents, so if you give that to the Hamilton Genealogical Society, even if (worst-case scenario) they can't find Ruth, they should be able to give you the name and address of the cemetery where her parents were buried and funeral homes in that area (if you ask).
Good luck!
Josephine