I just turned 61 last month. Started with a little mountain biking about 10 years ago, then got interested in road biking about 3 years ago. Last summer was the first time I really rode very much, nothing like the 50 and 60 mile rides I read about in these posts. I ride mostly alone, and would love to do longer rides if I had some companions. I live in the western mountains of Maine and there are no bike clubs near me. Some of our roads are pretty treacherous (logging trucks, etc) so I am careful about where I ride.
Last summer I got more ambitious as I had to get ready for a 2 week bike trip in New Zealand. That was a blast, BTW, and I hope to do more group trips.
Winter is for skiing--here we get 6 months of winter, 6 weeks of mud season, and some pretty cool biking on both ends. But June thru September are pretty great! You California riders are pretty fortunate!!