So the next day? That works for me :)
I was thinking they would get separated because the local knights would figure out they're from Brerra somehow (probably William screwing up his accent/not trying)
Maybe Hartley comes with Crow and Penelope initially, but something takes him away later on?
I could think of a few scenarios:
-Hartley runs into an old flame at one of the towns they pass through and stays to reconnect
-At some point, Crow and/or Penelope end up revealing their feelings for each other and Hartley finds out (he leaves because he can't get with Penelope anymore)
-Trouble happens and he gets killed

I just think that in the initial separation, he's gonna find a way to stick with Crow and Penelope because of how stubborn he is