OK. Thanks for the advice.  We'll just have to give it a try.  It's for our own amusement.

If it's an electric piano volume won't be as much of a problem.
As far as what to play, play what you know even if it's noter drone. It wil all sound good. Your friend will just have to find music to accompany you!

Dulcinina, a while back I asked my daughter to play the piano while I played my dulcimer. Unless you are amplified in some way the piano will overwhelm the dulcimer. I'm no expert but unless I was wired my acoustic dulcimer was no match for the piano, especially when my daughter hit those keys, LOL 

A friend who plays piano wants to accompany me as I play the dulcimer.  Any of you have suggestions for suitable music?  I'm an intermediate/beginner so it needs to be simple.  I was leaning toward hymns but am open to any suggestions.  Dulcinina