lucky he was a wesleyan - there was a regularly updated book - Hill's arrangements - that lists all the circuits a preacher had been stationed at.
however my copy dated 1887 only gives those still living - william is shown as commencing in minstry in 1798 and died 1823 so possibly an early edition might give his stations

For most methodist research it is worth contacting John Rylands library (part of Manchester Univ) - see http://www.library.manchester.ac.uk/specialcollections/collections/methodist/