First, Tristan's song, the one that makes me think of him, is "Easy Silence" by the Dixie Chicks.
The easy silence that you make for me
It's okay when there's nothing more to say to me
And the peaceful quiet that you create for me
And the way you keep the world at bay for me.
As for songs I listen to while I ride? I don't listen to music, but sometimes when Tristan is fidgety, I sing to him. I always sing Cole Porter mashups, seguing from one song to another depending on the pace and what lyrics I can remember at the moment.