If the files are already on some kind of media, you should be careful to make a working copy of them so as to have a fall-back, just in case something goes wrong in the process of trying to access them.
There is a possibility files from one era may be read by more recent software, and upgraded by that software; this may be OK. But do not let such as process convert the originals, just in case that does not work or damages them instead of converting them.
To know more exactly what the software was, and the version, would be more helpful when looking for a vintage computer and software sets for this kind of project. If the originals were created in AppleWorks or some other, that may be easy to open; older versions of MS Office or Word may be obtainable. A local Apple User Group may be a source of some information or leads.
Good luck with your project...!