Hey, thank you all for the continuing suggestions.
Some of these places I did see or drive through on my earlier trip (Grand Blvd and New Center, and a very quick spin through Hamtramck as part of a drive-by of the Ford Highland Park plant), but these additional tips are good. I definetly want to squeeze in a visit to that Eastern Market as I am a fan of these old urban markets, like Western Market in Cleveland and Findlay Market in Cincinnati.
Here's something I found online...
Detroit, A National Register of Historic Places Travel Itinerary
So much to see! I won't be able to do this all as I plan on only three full days, and a part of Sunday will be attending a panel discussion at the Cranbrook site (I will be going in early March).
Also, one of the things I wanted to see, the Saarinen House, won't be open till the late spring, so definetly another trip later in the year.
As for Cranbrook, how long of a drive is that from downtown, on either Woodward or via freeway?