I have some files in WriteNow and WordPerfect format. The WriteNow files go back as far as 1987 and the WordPerfect files are from 1998 – 2001. Some I can read, others I can't open at all. Those I can read lose most of the formatting.
I'm talking basic "RTF-like" formatting for the most part, not super obscure proprietary word processing features à la the Home Depot that is MS Word. There are also some embedded graphics in whatever was the generic standard for Macintosh back then.
Even if a file might be in RTF, that standard has changed significantly over the years and formatting is lost for the most part.
I don't have the original software or a machine to run it on.
Best Answer
for WordPerfect documents, you can also try to use OpenOffice, LibreOffice, NeoOffice (...), libwpd filter (see http://libwpd.sourceforge.net/features.html ) will then be used to convert the document in odt format.
For WriteNow files, the best solution is probably using an emulator. If you have access to a 64 bit Intel Mac with OsX 10.6 ( or 10.7), you can also find on http://sourceforge.net/projects/libmwaw/files/ a precompilated version of a WriteNow filter to odt : mwawOSX.zip ; ie I tried to write a small filter to convert WriteNow files, it works "well enough" on the few WriteNow files that I had found, so maybe it can work also for your files ( or maybe not :-~ ).