Peaceful!

A very nice song, gives one a lot of inspiration.
I read that you have problem continuing the song, know the feeling :(
Personally I think that you should build up the song more with the strings and the bass but not let them take over the piano, a harp sounds nice :)

I don't really like the idée of a flute or oboe, but it's just because it does not fit in with how I feel the song.
But that's just me, write it the way that feels right for you and it will be awesome!
Thanks for sharing this beautiful song!