I found a six-line poem beginning with the "picnic by the precipice" line but I don't think it's the same poem. It's dated 2002, which is way too recent for REUBEN, REUBEN. Behzad Bayati (Konrad Van Orton) not only claims authorship, he also put a strong warning on the page not to reprint the lines without permission of the author--and the author is NOT MENTIONED on the page. Check it out if you like:
[
www.geocities.com]
On another webpage, this much is posted and is attributed to a poet named Mordechai Vanunu:
Let's spread a picnic on the precipice,
Eat, drink and be merry with our backs
to the abyss
So now I'm intrigued. I will go to the library and look for the DeVries novel and report back.