This out-of-print book contains the only English translation of The Travels of Benjamin III. Amazon.com has a few, used copies of it.

Take a look if you're interested. I already bought mine.

The hero of The Travels of Benjamin III is a fool in a town full of poor Jews who barely manage to keep themselves alive. Benjamin is struck suddenly by a desire to travel, and joined by Sendrel he sets out to find a Jewish kingdom mentioned in legends of the Ten Lost Tribes. They hardly make it around the block. Barely escaping from their own wives, the two travel only as far as nearby towns. As the novel progresses they fall into the hands of Jewish kidnappers, who take advantage of their naiveté to sell them into the czarist army. They are caught when they try to escape, and the army’s response to this treason is a delicious twist that leaves the reader wondering who exactly is insane – and where precisely the line is drawn between an absurdity and a worthwhile dream.
(Summary by Omri Lernau)