Think of the Best of Turkey tour w/o hot weather. What's weather like in November and March?
I took this tour last year in the latter half of October. I used my warm jacket and my bathing suit (at different times). Istanbul was delightful, central Turkey could be chilly especially in the early morning and in the evening, and we swam off a boat on the southern coast. Ephesus was kinda hot but not unbearably so. If you get chilly there will be opportunities to buy a cashmere scarf. But I would pack a few items to layer.