A mother and father for whatever reason didn't want to be parents anymore, so they stopped at an amusement park (I think it was closed?) to let their kids go to the bathroom and when they came out of the bathroom, the parents were gone. The kids avoided the police because they didn't want to be separated. The kids were various ages and if I remember correctly, it was the big sister who took charge. Anyone have any idea?

Possibly Broken Promise (1981) (TV) (http://www.imdb.com/title/tt0080471/)

I believe that is it. Thank you! Now to find out where I can watch it. :)