Iran, Iraq and Syria have already given them overflight permission. They would come in over the Caspian.
Right through the gap between Turkey and Jordan.
They can be intercepted anywhere over Iraq. They will need dozens of daily flights which can’t be hidden.
Both the Saudis (F15s) and Turks can make this into a gauntlet. And unless the Russians can get the Iraqis to let them not just overfly but base there (joining the bigger war), no escorts.
BTW, counting noses, it looks like the Russians have 1/3 to 1/4 the air transport assets the US does, and 1/10th the air tankers.
Look, this is simply a poor strategic position. They have extremely insecure logistics and have popped a major base on the wrong side of an enemy power. Whatever else they may do to Turkey, in Syria the Turks can have their own way.
The flight path would be over Caspian, Iran, Iraq and Syria. Same as their cruise missile strikes from the east. The Russians already know Obama will back down. That occurred when retard Kerry blurted, what do you want me to do, go to war with russia ? Not even on the table.