I didn't much like either ABC or LRFtools, finding their output to be poor. The best luck I had for converting non-drm lrf to epub was a combination of calibre and "lrs2html.rb", a script available here:
http://www.spontaneousderivation.com...e-rough-guide/
Probably works best under linux, but I had fairly good results with the chain lrf->lrs->html->epub, using calibre for the first and last steps.
This guy proved Kovid's assertion that most of the work was already done!
Cheers,
John