Topeka High School is on 10th street a couple of blocks down from the Capital. I don't know the actual crossroads, but I know it is between Topeka Blvd. and Washburn Avenue. You can't miss the school. It is huge.
If you are coming from the Topeka Expocentre which is where kids state is being held the same weekend, you would take Topeka boulevard North to 10th street and take a left. the school is about 15 seconds from the intersection on the right side of 10th street. If I am wrong about that someone please correct me so no one gets lost.