Tahoe Dirt Girl, I understand what you are saying. It is hard to break into social circles here in MA. I say that as a native who has lived in both the west and the south. People are less transient here and are more bound up with families, parents, or the friends they have always had. It is not as bad now as when I was a kid and I think it varies from town to town. In AZ, whenever a I met a new person who I seemed to have something in common with, I invited them to dinner. Many friendships developed. When I moved back here, I tried that and everyone who I invited canceled "suddenly" before the date. I made my friends here through volunteering at my synagogue, the gym, work, and once in a great while, a parent of my kid's friends. When I moved here my kids were young, but already in school, so I was not involved with "play groups."
I say find a common interest, whether it is cycling or something else and keep trying different groups until you click.
I am now in the position of having outgrown the friends I made here 18 years ago. One in particular is like a relative that I don't want to be mean to, but I can't stand listening to. We spend most of our time with friends we met through cycling. They are a little younger than us, but they don't have kids and since ours are grown, we are all free to come and go as we please. They pretty much lead their lives around cycling, x country skiing, and eating out, so it's great. My other friends think our outdoor lifestyle is crazy and I am getting sick of their attitude.