After visiting Detroit, drop down to I-70 and head due west to Denver, then north about 40 miles to Boulder. There you can visit the Shelby American Museum. You will see many original Cobras and several original GT40's. Just make sure to check the hours to make sure they will be open when you arrive. From there you can head south along the front range of the Rockies, then west to Airzona. The scenery is awewsome.
Chuck
Shelby American Museum