Sorry, thought that you know the area.
I'd suggest a one day road trip:
West on In 32 to Crawfordsville (Wabash College)
South on In 231 to Greencastle(DePauw Coll.)
South on 231 to US 40, east on US40 for 3.8 miles to Mt. Meridian, then south on Co Rd 550E for 1.2 miles to Putnam Park Road Course...watch PCA lap, eat limited lunch...retrace route to US 40, go back west to 231.
Go south on 231 thru Cloverdale to Spencer ...take In 46 to Bloomington (IU).
East on 46 thru Brown Co to Nashville...stay on 46 to Columbus...then I-65 to Indy...taking I-465 to Exit 31..which is US 31...go north 10 miles to Westfield.
Call if you get bored...or lost...or need more!!!
This is a great Miata route!!!