Good news (and, depending on your viewpoint, terribly bad planning) - there are CAMRA beer festivals next weekend in Wigan, Oldham and Leeds.
The first two are covered transport wise by a Greater Manchester Rail Ranger (£4), which covers all railway services in the GM area. There are also tickets which allow bus, tram and train, and any combination.
My inclination is to do Oldham, and then travel across the Pennines by the scenic Calder Valley line to New Pudsey (for the Leeds fest). Be warned though, both Festivals close for a couple of hours from 4pm, and to my uncertain knowledge, there are no decent pubs nearby in New Pudsey.