You will find the information needed to solve for the final coordinates at the posted coordinates.
N 35 AB.CDE / W 090 FG.HIJ
A= the 2nd digit of the interstate highway in the title of this historical marker
B= Note the year that the Supreme Court ruled that the state could not build the interstate through Overton Park. Add the last 2 digits of that year to get B.
C= the number of letters in the state that wanted to build this interstate through Overton Park.
D= the first digit in the interstate emblem at the very top of this historical marker.
E= Look at the date range just below the interstate emblem at the top of the marker.Subtract the last digit of the first year from the last digit of the 2nd year to get E.
F= the last digit of both the interstate highways mentioned on this marker.
G= the 4th digit minus the 3rd digit of the year the U.S. Interstate system was established.
H= the 2nd digit minus the first digit of the 3-digit interstate highway mentioned on the marker.
I= the last digit minus the first digit of the year that the U.S. Supreme Court made the ruling.
J= the 2nd digit minus the 3rd digit of the year the U.S. Supreme Court ruled in Overton Park's favor.
For extra credit, message us (do not put this spoiler into your log) and tell us what you believe the intended purpose of the site of the final was. We will respond and let you know if you are correct.
Please be aware that the final is almost exactly 2 miles from stage 1 as the crow flies - probably further than you will want to hoof it.
Congrats to Shottsy as FTF and for correctly answering the extra credit question.
You can validate your puzzle solution with certitude.