well, the uilleann pipes (especially those with full registers!) ARE slightly easier than tying your shoe whilst fending off a swarm of bees during a ski jump in a hurricane...at night...while drunk.

But for making tunes easily, I would go with a recorder. (no tuning like an autoharp)...the mountain dulcimer is pretty easy also, and is not TOO hard to tune. The recorder can be carried in a pocket and practiced almost anywhere.

Even easier...just learn mouth music! *grin*