I assume the backrub train is how the ghosts cash their back rubs in.
As a writer, I get why they made this change: Thor and his son having a conversation for the first time in a thousand years face to face is drama.
Thor and his son having to yell their heartfelt feelings across huge lawns is comedy.
Plus, one of the longrunning themes of this show is that it's difficult to be a ghost. It's rare for people to be able to see them, their powers are weak and ineffectual, possessing a host is rare and dangerous. So, again, as a writer, I get why they didn't want to make it easy for Thor.
As a fan? It feels cruel! It kinda bummed me out a little, I'm not gonna lie. Though part of that is a credit to the show: I've fallen so in love with the characters they've created that I only want good things for them all! Which is not conducive to comedy!