The lower right corner of the Edit Person window shows the sentence that will be generated for the highlighted fact, and also has an option to customize the sentence. That option can be used to, for example, rearrange sentence variables such as [Date] or [Desc].
However, as far as I can tell, it can also be used to write a sentence, or sentences, that make no use of the variables at all. In the limited testing I have done with narrative reports, the sentence prints correctly and is properly footnoted. This seems a better option to me than worrying about the size limit on the Description field or using the Note and having the footnote number appear between the sentence and the note rather than after the note.
In TMG, I used an Anecdote tag whose generated sentence consisted simply of the text typed into the Memo field. In RM, I can't use the Description field for that because of the size limit. I'd rather not use the Note field, because I can't control including the note in narratives on a Fact Type basis and because the footnote won't be in the correct place. Is there any reason I can't just type what I want in the Customize Sentence window?