Looks like a very interesting idea.

Which cities are you planning to visit? Tehran, Qom, Tabriz, Isfahan?

Does anybody has any idea of land travel in Iran?? Is it secure?

I can easily fly domestic IST-VAN on TK and take a bus from VAN to THR. The 10-hour-busride would cost me appr. US$10-15 one way. A little bit long but very very cheap for me. (And for your information Van is the border state of Turkey to Iran and a fascinating city by the Lake Van and Akdamar Island in the middle of the Lake Van with a church from eight century!)