That's a good idea ,a Part II will help as I'm in the same boat having never visited Preston before.Besides the three you mention ,I would also like to try Plau,Vinyl Tap,Moorbrook and Princess Alice as I'm just coming for the day trip.I was thinking of the Plug & Taps on the way back to the station.
I've got a guest coming along who has never been on a PuG crawl but was brought up in Preston and is keen to revisit some of his early drinking haunts and also see the newer ale scene.