Another Unexpected Journey

Bilbo Baggins left Frodo behind on their birthday to leave for another adventure he had no intention of returning from. Bilbo reaches Erebor and returns to Rivendell where Frodo finds him after he gets wounded by the Morgul blade. I't kinda a headcanon, since you can't convince me that Bilbo sat in Rivendell and wrote poetry for almost twenty years. Could be slash if you want.