You mentioned "Low-Maintenance." Provided that they are properly set up when purchased, lap dulcimers don't need much maintenance work except when a string breaks, and if you learn to tune carefully that will not be often.
It's best to store it in a proper case, rather than a pillow case. Try to keep the case out of the rain, and don't leave it on a beach. Wiping occasionally with a soft cloth and maybe oiling the tuners every couple of years is a good idea.
The traditional dulcimer is reputed to have been kept hanging on the wall over the fireplace in a cabin which wasn't heated much in below zero weather. If well built, they are a tough as the Kentucky hill folks who owned them.
I'm assuming you didn't buy one made with faces of glued up exotic wood with wild grain or knots, or millions of sound holes, and that it has a proper one-piece fretboard and geared tuners. Buying exotic stuff is always a risk.
