Sorry, I’ve been really sick the last few days so I guess I just missed that part. We actually do know pretty much where they all are as Vendeya is essentially modern day India and Kambuja is the equivalent of the old Khmer Empire which has shrunken enormously and is now modern day Cambodia. (The Khmer empire was also refereed to as Kambuja).
So, as you can see from the map below if you sailed from Kambuja you would cross Vendya before rounding the southern part of what would become Africa though it is not as large of a landmass as it will become in our time, and as you travel up the coast the Isle of Sipta is actually on the map as well (though they list it as Siptha’s Isle). Since, as pointed out, travel by ship is how most people are marooned here, this is still feasible.
