Ah but see you could edit the txt file to your heart's content and then leave the _words_ for txt2lrf to take care of. Thereby reducing the amount of manual labor you need to put in. The *2lrf tools don't force you to do automatic conversion. I don't know if your familiar with TeX, but their philosophy is based on it. Think of them as the last stage of a toolchain, like a compiler. You prepare the sources (TXT or HTML files) and then compile them into machine readable output (LRF file).
Indeed txt2lrf was designed with the goal of allowing perfectionists like you to edit the TXT file to your hearts content and end up with a TXT file that looks good by itself and that can be automatically converted into a pretty LRF with images and a TOC and what have you.