I am converting a collection of spoken word audio tapes to MP3 format so I can listen to them on a portable MP3 player. The original tapes are well recorded.

Can someone suggest what the appropriate settings would be in the Lame MP3 encoder for spoken word files?

I normally use the --ALT PRESET STANDARD settings, but this seems like overkill for normal speech.

I could be wrong but I believe that <128kb encoding should be done with the fraunhofer codec? I could be wrong but I think vbr is not good for lower bitrate which spoken word is usually done in.

This has been discussed multiple times. You might want to use the search function (e.g. search MP3 forums for topics containing "speech"), you'll find e.g. this.

A good starting point if you want to use lame might be
--alt-preset <...> -m m --lowpass <...> --resample <...>

Important: Some portables might have problems with certain sampling rates or even mono files.

I use mostly mono 56/22 FhG.