What Londonkiwi says about going from cold and wet to warm and dry a bunch of times is true (for just about any pub crawl I've ever been on). Why does it always rain on pub crawl nights? Not that I've been on one for many years... Anyway, back then I didn't fuss much about my clothes. I mostly wore some variation of heavy leather boots, jeans, and lightweight top, bare arms, and a warm heavy coat I could take off the coat inside. I'd probably still wear a variation of that. Pub crawls usually involve a lot of sitting and drinking, and not really dancing, so what you wear on your bottom half won't matter much for the indoor parts. And for the outdoor parts, you mostly want to be able to walk and not have wet feet. Your riding boots seem a good idea.