This route is through Asiatic Turkey. Starting at Trabzon on the Black Sea, leaving the less than desirable port of Trabzon, head out on the D885 for Erzurum on the D885 toward Gumushane, the route follows main roads, otherwise it gets a bit too much like the Dakar Rally. You travel through stunning mountain scenery and get to see the side of Turkey that you miss in Marmaris. Pick up the D050, then the D915. The mountain passes near Bozurum are stunning. You will eventually get to Askale, near which you pick up the D100 to Erzurum. The route is on fairly broken roads and the local driving would make a kamikaze pilot wince, but if you are brave it is worth it. You can do the full Judith Chalmers thing in Erzurum, eat a proper Turkish kebab, eat the pastries, a good route for potential explorers. Take a map as there are very few English speakers outside of the cities. Petrol stations are quite rare, so fill up when you can. I think the route is around 250km.