Best starting point for arranging music?

I would like to arrange some popular/modern songs for the dulcimer, but lacking dulcimer-specific sheet music, have a question how best to start.  I'd like to begin with a simple version of the melody, so I don't have to pick out all those notes from scratch to start.  Should I try sheet music for piano to provide that starting point?  Other suggestions?  And good sources for such things (I'm not sure there is a suitable nearby store to go browse...).

Thanks!

Lisa