Thanks for the valuable guidelines Candace! Much appreciated!
Ginger purrs when she runs now - it's a really nice sound so I reckon she must be "good to go" too.
She was sluggish and slow when she first arrived. I cleaned so much old gunk off of her innards. Someone had a long time ago put about a tablespoon of lubricant on each gear and it had flung all over and dried on top of the gears in big tacky blobs. There was plenty of evidence that they over oiled her too. After cleaning, I oiled and lubricated her gears as shown in the manual, being quite careful not to over do it. I was just worried that if I oiled her after every day of use that I would end up with too much oil on her. So I will do as you wrote and oil only some of the areas that often.
I sent my tube of Singer lubricant off with my daughter so am definitely going to buy the Triflow as the replacement. Everyone sure says good things about it.