Not being a joiner myself, I say give the book club a try. You can always back out if it's not to your liking (and cite something like scheduling or distance or bedtime issues or something practical like that so as not to offend), or just show up when you can/want to. I was in a book club/dinner club thing for a little while (until the organizer moved away) and it was fun - and far less join-y than my more concrete adventure in joining things, which involved a commitment and actual work (not so fun). But this doesn't appear to involve much of a commitment and very little work.