I would highly recommend that you get hooked up with the local hospice people. This is certainly going to degenerate to a point where her resistance to pain meds is going to go away. Driving is something that you should monitor carefully since she may endanger herself and others as this disease further impares her abilities. The onset of those impairments may occur suddenly, and given her desire to go to church so frequently, she may be driven to take herself there even with compromised abiities to do so. But the hospice people can prepare you for all the events that are going to transpire and have the entire family prepared for what is going to be needed and what to expect.

If she is not eating and dropping weight rapidly, various medical conditions could actually accelerate her death before the cancer. This may or may not be her desire. I suggest that you email Gary on this board who has been through training in much of this including hospice care, and who will be a source of information for you beyond what most of us here can offer. We have few posters that choose to let the disease run its course.