How do I determine what's the best facility to put my parents in?

I am an only child (living out of state) of elderly parents who are fast becoming unable to live independently in their own home due to declining physical abilities, memory problems and my concern for their safety. Where can I begin to find information on facilities that will admit both of them? My wish is for them to stay together as long as possible however I realize that each of them may have different needs at different times. I don't know if other people have found themselves in a similar situation but sometimes I feel that certain facilities such as Assisted Living facilities may not provide enough support for my parents and Skilled Nursing may be too much at this point. Is there a happy middle ground? Thank you.