you can do this...
coming from ST. Joe,
take I-29 south to 435 west heading south,
take 435 south to the I-70 interchange head West,(right coming from the south)(you will go bye the new speedway
approx, 6miles exit at Leavenworth,exit, just past the race track, Will say last free exit.
you will come up to a light at the end of the exit, head Right and take your second Right on K-7 and you will be at Sandstone,
Or when you are heading south on 435, take State AVE, Right to sandstone, You will go around the NEW State AVE, and get a better view of the New speedway. about 2 miles after the speed way you will see the entrance to Sandstone on your left.
Hope this helps