I had forgotten all about this episode of "Alf", in which Gordon Shumway (Alf) dreams that he is stranded with the cast of "Gilligan's Island". This episode, which premiered on September 28, 1987, is the last time that Denver, Hale, Wells, and Johnson performed together. Hale passed away a few years later, on January 2, 1990.
In the dream sequence, he meets Gilligan (Bob Denver), the Skipper (Alan Hale, Jr.), Mary Ann (Dawn Wells), and the Professor (Russell Johnson). Though their island life looks ideal on-screen, the castaways have been shipwrecked so long that they’re sick to death of all the things that ALF fantasizes about. The absence of the other castaways is explained by saying that they live on a country club on the other side of the island.
If you enjoyed either show, now you can enjoy them both by watching it here, thanks to Hulu.com.