Here's a link to my map of good pubs in Lincoln, from the initial thread on the autumn crawl, though I expect there will be changes when the new edition of the guide comes out in a few weeks:
Maybe the best way to start is a bus up the hill. The bus station is very close to the railway station, and there are
buses every few minutes (4, 5 and B5) to a stop that is a little bit past the Adam & Eve, a GBG pub.
From here there's
a short walk, very slightly uphill, to the Morning Star, another GBG pub. (Both this and the first one seem to be open from noon on Fridays.)
From here it's
another short walk past the Cathedral to another GBG pub, BeerHeadz, and
then past the Castle to the Strugglers, a fourth GBG pub. There are plenty of other good pubs around this high part of the hill.
At the opposite end of town, the High Street stretches out for what can seem like miles, to the Golden Eagle, a Castle Rock pub that is also in the GBG, almost a mile from the station. Also in the GBG is the Tiny Tavern (but this doesn't open until 3pm) and the Ritz, a Wetherspoons. It may be that there are enough pubs in the northern part of the city to keep us occupied without bothering the High Street pubs?