As I addressed in an Comic Book Urban Legends Revealed installment awhile back, Steve Englehart was not pleased with his departure from the Fantastic Four, but more importantly, he was not pleased with the editorial decisions of Marvel.
Specifically, he took issue with what he found to be essentially arsticially stripmining the works of Stan Lee and Jack Kirby. During Englehart's run on the Fantastic Four, he tried to move the characters in a different direction than the classic Lee/Kirby Fantastic Four, particularly with the roster of the team - having Ms. Marvel and Crystal take the places of Mr. Fantastic and Invisible Woman.
Already, there had been interruptions with his storylines, but when Englehart was told that he basically had to return Mr. Fantastic and Invisible Woman to the team, Englehart balked, and as I mentioned before, went by the alias "John Harkness" for the remainder of his tenure on his book.
His last storyline, though, was a direct protest to editorial.
The Dreamquest Saga involved an alien who trapped the real Fantastic Four in dream-like stasis while having a fake Fantastic Four go about their business on Earth. This Fantastic Four was essentially the 1961 version of the group. Basically, Englehart's way of saying, "You want to go back to Lee and Kirby? I'll give you Lee and Kirby...EXACTLY!"
In Fantastic Four #329 (drawn by Rich Buckler), we see examples of how Englehart decided to handle this.
See Mr. Fantastic here...
Now check out Mr. Fantastic in 1961's Fantastic Four #1...
Here's a couple of others...
Meanwhile, while in stasis, the members of the Fantastic Four have dreams of different stories. These stories are, more or less, are condensed versions of the stories that Englehart was planning on telling had he not left the book.
Finally, at the end of the comic, after the Fantastic Four have vanquished their clones (and a bunch of superheroes show up to help out, including, specifically, at the end of the issue - Captain America, Doctor Strange and the West Coast Avengers...hmmm...I wonder what they all have in common?), Franklin Richards takes everyone on a trip to California.