At that time of the year, the only realistic overland route is via Iran and Pakistan. The route through Central Asia will lead you to the high mountain passes in Pakistan or India, each with associated problems including winter-time closures.
And you should definitely visit Iran. The roads through eastern Turkey to Doğubayazıt, for example, will be open (or be open most of the time) with regular bus services. From Doğubayazıt take a taxi to the border and walk into Iran. Find a ride to the bus station and then ride in comfort to Tabriz, or beyond.
Or take the weekly train between Turkey and Iran, joining it from Van or a point further west: http://www.tcdd.gov.tr/tcdding/ortadogu_ing.html
The stickiest part of this route is the sector between the Iran/Pakistan border and Quetta, the first major city. You should not approach this sector lightly. Travel is slow over poor roads, it's quite isolated and there are regular attacks on Shia pilgrims and sometimes targetted kidnapping of foreigners. Two Czech girls were taken from a bus in early 2013 and nothing has been heard from them since, apart from a video released in October 2013.
On the other hand, a Finnish traveller recently posted his account of the crossing
(Trip report: Taftan to Quetta border crossing Nov 2014). He reported that 11 other foreigners had made the crossing that month.
Depending on your appetite for risk, you might consider a flight from Zahedan in Iran to Quetta or another city in Pakistan. Once you get past this sector, however, travel in Pakistan is a breeze. Make sure you allow some time to explore Lahore, and to view the daily ceremony marking the closing of the border between Pakistan and India.
See more on these matters in the Pakistan branch.
The further complication with travel via Pakistan is that you will need to obtain your visa in your home country. It's not possible to pick one up anywhere while on the road.