@mitch if you have the original in a format that lilypond can import, you can define your own StringTuning and output dulcimer tabs. Might need to transpose it up as I assume the dulcimer can't hit all the notes on the guitar fretboard, and maybe invert or thin out some chords to get them to one note per string, so not entirely an automated process but reasonably doable.

See e.g. the third example at https://lilypond.org/doc/v2.25/Documentation/notation/custom-tablatures