I like to think that Uruka's route is the canon route since it has all characters present during its run. It also shows Nariyuki struggling to comprehend his emotions about her and even asks his dead dad what to do. It shows that all other girls support his decision and back him up to run after Uruka. Its a good end, but lacks the lovey-dovey stuff except for the proposal in the end, which is fine for an ending since it ties up loose ends.
Rizu's route is... weird. I already consider it non-canon since the route starts at the Christmas arc, where Rizu asks to play a game with Nariyuki (which never happens in the canon story). It follows the "main" Uruka route except this time Uruka never confesses. I call it the "wacky" route since it had it's own sub-plot with Sawako, and the inclusion of the ghost being a main character.
I'm expecting Furuhashi's route to be the more "romantic" route, where-in everything plays out exactly like Uruka's route until the accident happens. I expect more lovey-dovey hijinks since Nariyuki is taking care of her. And it is also safe to assume that Uruka won't confess either just like in Rizu's route.
I like how they just change or add one thing to Uruka's route to shift it to another girl's route. Feels very VN but not quite.