to be specific is like asking the length of string. a club in Winter, on a rainy day might well only do 30-40 miles and no cake stop, but yet in the height of summer, will cycle to the coastline for fish and chips before returning, a club like mine that's around 120 miles there and back.
Also some clubs have a slow group and a fast group
If you was to ask the club you intend on joining how fast tehy go it might be a better indicator.
for example, In your situation your better off looking for a touring club rather than a racing club.
Some clubs treat club runs like chain gangs, and that's where the snobbery will shine through, as they will be off like a rocket, and no one really wants to have to wait behind for the new lad with the kick stand and flat bars to try and keep up. Alot of clubs around London, (especially south for some reason) are exceptionally friendly, ring around.