I grandly appreciated all your suggestions. I concur that inventing folk names for the geographical landmarks would fit, but I'll try to make it coherent in a way that the reader is able to deduce the actual locations.

You've hit the spot with method #2. One of the better sounding names I came up with was Regsmarkos, a clumsy attempt for the proto-indo-european of "horse master". Others were just awful and lengthy, with too many consonants.

Unfortunately I don't have space to include an appendix.