Travel books

I need to begin preparations for my eastern European odyssey, which begins August 9th and ends September 3rd. I had planned (for months, ever since I read about it coming out) to take along the new translation of Don Quixote, a book I've never read before but should. However, said tome is still only available in hardcover and is a giant brick, which militates against its being brought on a trip which requires me to live out of this backpack for four weeks.

So: does anyone have any suggestions for alternative reading material? It should be:

-Challenging, if not an acknowledged classic; I read very quickly, and this needs to last me for the entire trip if possible. I tend to read on planes and trains and at night, so typical summer beach books are unsuitable no matter what their page count. No religious texts.
-Available in paperback and preferably small.
-Something I would like. I prefer fiction to non-fiction.