Dealing with elderly parent while on the road

Your mother cared for you and was tied down when you were a child. She was in her prime when you needed close supervision for almost 20 years. Is it too much to ask that you take care of her for a few years? What if she passes away while you are traveling? I am certain you will feel pretty guilty that you didn't want to be bothered with her for a short period of time. I realize my remarks are harsh but I was not given the opportunity to be with my mother towards the end of her life and I have always regretted it.
We have a friend who brings her mother with he whenever she travels-even the mother's dog travels with them!