I gather by NW Michigan you mean the NW lower Peninsula and not the U.P.
As for the NW lower, Leelanau County, immediately northwest of Traverse City, is wine country as is the Old Mission Peninsula. The Peninsula would be my choice for a few day stay, a pretty area with a lot of cherry orchards, vineyards and some nice vistas of the east and west bay. A lot of nice little restaurants and a number of wineries you can visit too.
About 50 mils west of Traverse City is the Sleeping Bear National Lakeshore with its outstanding sand dunes and great views of Lake Michigan.
As jaredangle mentioned, Charlevoix is nice little town as is Petoskey further north. If you do Petoskey, be sure to drive through Bayview, which is a large area of 1880's-vintage Victorian homes. Also drive M-119 (called the "tunnel of trees") north out Harbor Springs for some outstanding scenery and great views of lake Michigan. Wilderness State park, at the very tip of the NW lower peninsula, is the largest State Park in the lower peninsula and very rustic.
It's a nice area which is why I live here, I'm sure you'll enjoy your stay.
Jim B.