I did 42 miles Saturday and it was 60 degrees and windy here. I had on my brand new tights from Performance. They are windproof on the front side, have a bit extra to keep the knees warm, and the backside fabric allows heat/sweat to wick out.
I had on a long sleeve jersey but it wasn't windproof and I was uncomfortable for a few miles until I warmed up. I wore the jersey the next day with a t-shirt underneath and that was a bit too warm. Also, the t-shirt holds moisture like a sponge, not a real good thing.
I had some nice wool socks for cycling. Worked great for that day's conditions.
I've ordered some windproof jerseys that still breathe on the back side and a couple of base layer shirts.
Make sure your jerseys have zippers in the front so you can regulate your temperature.
A headband that covers your ears is a lifesaver, too. Make sure it can wick the moisture away. When it gets colder, I'll put on my shoe covers(not booties) to keep my feet warm. And full-fingered gloves.
Make sure you've got your fans stationed at the tops of the hills so they can hand you newspapers to stuff in your jersey. It'll keep you toasty on that descent.