I am 56 and your mom is not an old woman. She needs to get out and make friends. Get a part time job, volunteer, join groups that have similar interests, take a class, join a gym, attend a church. find some outside activities that she enjoys.

Since she lives in such a rural area, it might be a good idea to move to where there are more opportunities to participate in social activities. She may even enjoy something like mmorpg once she was introduced to it. There are facebook groups that are for specific cities/areas or for specific interests that she could find local meet ups.

Don't sacrifice your life for your mom. She has options, she has to decide what the rest of her life will be. I encourage my 26 year old daughter to be independent and to chase her dreams. The time for her to make mistakes is now, while I am here to pick up the pieces if needed. I am her safety net if she needs it. She isn't my safety net.