Take note of this quote from the article Posthumous Crichton Novels on the Way:
Ms. Nesbit said that Mr. Crichton left “many, many electronic files,” and that there could well be other novels or unfinished material. “We haven’t begun to really go through it all,” she said.
So who knows what else may be there? In an online discussion in Nov. 2005, I asked Michael Crichton if there would ever be a sequel to Travels. He said:
Actually, I have been trying to get a sequel to Travels finished for quite some time.
I don't know how it happened but it has been almost twenty years since that book...
Links and more info on Michael Crichton at: