I usually don't fish the spawn (fishing for other fish), but I would recommend contacting your regional biologist with the KDFW. My experience is that they are very helpful. I have gotten tips not only on when to fish but even precise locations. I have in the past fished the South Fork of the Cumberland in Feb and March and have done ok (nothing to brag about). I have also heard that the Laurel River above the lake near the Corbin dam is also good. I will say that the run will vary with weather and water conditions. A lot of walleye fishermen in Ky are very tight lipped. It is almost impossible to find out anything on the web.
Good luck