OP, my Dad currently lives in a place much like your parents are considering. Independent living, meals in the dining room, transportation, etc.
I'm not going to say exactly what his costs are, because I don't have permission to share that information.
What I will say is that the price of his place here (Idaho) is about half or even less of a comparable place and living arrangement in California.
Also, it is probably three times my all in living costs (I live in my own house, have a car, and live a typical suburban lifestyle).
The price of assisted living or memory care raises the price significantly (+50% to +100%) and lowers the quality significantly (-30% to -50%). So if your Mom might need memory care, you probably will want to look at what those costs are and see if they are viable long term at this place. If the memory care there is too expensive, you may want to look at less expensive options now so you can afford the memory care later. Or you may run the risk of moving your Mom to a new place right when she's declining and possibly emotionally vulnerable.
At my Dad's place they have independent living, assisted living, and memory care. If your Mom might need memory care, you might want to visit that part of the place and make sure it's acceptable.
At my Dad's place, it is extraordinarily expensive to maintain an independent living arrangement for one spouse and memory care for the other. I think in that situation, many couples both move into assisted living or memory care when one needs it.
Although assisted living is expensive, most people who move there don't seem to live more than a year or two longer after their move. Memory care is similar although some people with Alzheimer's can live much longer (5-10 years maybe).