Yeah your temperature range is pretty wide really. Basically it comes down to your own personal warmth level (for lack of a better description) and the temperature. There's no one right answer especially with that temp range. When things get under 70 deg for the entire ride I start thinking about things like base layers, arm warmers and knee warmers along with heavier socks and or toe covers. Also very possibly a vest. A bit cooler and I'll go to a LS jersey, full finger gloves, ear cover...say when it's low 60s and a lot of 50s. Get into the 40s and I'll put on tights (I hate leg warmers) over my bibs and break out the thermal jerseys (I have 2 of them) and think about insulated gloves and shoe covers. Ride in the 30s will be my Assos winter cycling jacket over a baselayer (this is some hybrid of a jacket and a jersey is the best way to describe it...VERY warm) and I'll go to cold weather cycling shoes and for sure insulated gloves and a helmet liner (this sort of hat with thin fleece and a wind stopping layer).

If you're going out for a specific road ride it's best to be cool not quite cold when you leave. If you are roasty toasty warm then when you get going and building body heat you will be too hot and then you've got to think about taking stuff off and carrying it and worrying about that sweat freezing.