You rang?
So, for the resort's trains, both in CityWalk and in UniSEA...
Hogwarts Express in UniSEA is meant to be a wholly
in-park experience, without the park-to-park element. It works the same as in Orlando otherwise. Loading in the Kings Cross station in the Victorian London entry land, then through Transylvania where it adds cool movement (riders are unaware; they watch screens), then unloading in Hogsmeade. Will be an out-and-back, not a circuit.
Additionally, boutique hotel guests staying in Hogwarts begin their visit with a secret entrance directly into Kings Cross. Like HP first years, they ride to Hogsmeade, then transfer to boats to reach Hogwarts.
For the CityWalk elevated train, I was imaging something which technically functions like this:
DisneySea Electric Railway.
@S.P.E.W, you seem to be a train guy. Would this count as a funicular?
No screens on this thing! The appeal is genuine views of a beautiful resort. Circuit or out-and-back, I'm fine either way. It can resemble another historical train, of course.
Incidentally, Space, your overall resort map seems fine. No issues here!