Scale of the Thurian Continent
Thuria is a slightly smaller version of Afro-EurAsia, and with a large polar ice cap.
It is 10,000 miles from Zingara to Khitai isles, considering geographical distortions from conversion of a flat-paper map to a globe. Midway is Turan.
It is 2,500 miles from the Western Ocean to the Nemedian mountains.
Thus Nemedia and Brythunia are about 600 miles across at the widest points, or the equivalent of the size of France. Aquilonia would be quite a bit larger 1500 miles across, depending upon what the Picts are up to that season...
I place the equator at the southern 1/3 of the Black kingdoms, just below the tip of Vendhya which wold leave that area a little bigger than is shown on the map.
The Nordheim ice cap is at 60-65 degrees which is about 2-7 degrees further south than the current Arctic circle (not current polar cap), or at about Estonia. This is actually pretty close to what we estimate real-world conditions to have been like (in regards to the ice cap anyway ;).
So, if you're planning on playing a game there, or need to calculate distances, just use France (about 600 miles) as your guide for Brythunia/Nemedia.
Using the D&D rules for travel, at a speed of 40, Conan could cover 32 miles per day. If the Kings' Highway extended from Zingara to the Eastern ocean, it would take conan 312.5 days to pull a Forest-Gump trip.
Vilayet Sea is 600 miles across at the widest point and about 1500 miles from north to south or about the size of the Red Sea. It is longer and narrower than the Caspian sea. Either way, the Red Brotherhood has plenty of room to sail.
It's 1200 miles from Agrapur to the Kezankian mountains, or about a 35 day walk across the steppes of the Kozaki.
To get from the Vilayet to Meru (when Conan was captured) it would take a while, considering jungles and mountains (.75 travel); about 500 miles or about 20 days.