There are several free versions here at Mobileread, hand-formatted with the Sony Reader in mind.
Prodigit's:
https://www.mobileread.com/forums/showthread.php?t=37065
TedPark's:
https://www.mobileread.com/forums/showthread.php?t=27252
Deputy-Dawg's:
https://www.mobileread.com/forums/showthread.php?t=19870
I believe they use different ways of sorting TOCs and so on; look over the descriptions and see if one of them sounds most like what you're looking for. Or download them all, and compare that way. They're free!