We took a Pub Crawl tour when on a Viking River cruise going thru Cologne Germany. It's wasn't a "HEY - LET'S PARTY" type of tour. We had a fun group of a dozen or so, hit 3 or 4 pubs and had one drink in each. The guide told stories and gave history of the city as we walked. It was alright. Glad we did it but wouldn't do it again. As you've said above, you probably WILL have more fun on your own just winging it. FoW is probably a must stop in, other than that, I'd say research pubs if you're really interested in pubs and hit the ones that tickle YOUR fancy.
We did venture out on our own in Sydney and took a water taxi over to the Taronga Zoo. A pretty neat set up. Take the ski lift to the top, then tour the zoo as you walk downhill all day long.