They wont. By the time Vale sold out, the vast majority of seats had been sold to City so all they can do is sprinkle themselves in, and I reckon they are just intent on enjoying the game like yourself.
It's Man City v Port Vale, not Stoke v Port Vale or City v Utd. They'll be traveling up with half and half scarves, buying souvenirs in their shops, bringing inflatables etc intent on a party. I hope!
It's more or less a local Derby. Stoke on Trent I think is the next stop on the train after Macclesfield? Neighbouring county to Cheshire?