Forgive me for being a little harsh here, but why are you asking? Do ou want to play beautiful melodies and songs with the least amount of work? Or are you only trying to accompany your singing/songwriting? If it's the former; forget about it. It takes years and years of practise to get to the point of being able to play any instrument properly.
And for that matter, those are supposed to be enjoyable years as you learn, understand, and appreciate the music. There are no shortcuts, and I think most musicians are glad thet their aren't. Half the enjoyment of playing an instrument is being able to see an improvement and to learn new things. For me, learning new things is the biggest thrill of all.
If it's the former, why don't you get a guitar, learn 3 chords, and get a capo? Or better still, get an autoharp.
Good luck