It seems such a tiny “thumb” on the map, and so, how could you possibly need a week? Trust me, you can easily do a week here. (Heck, lots of folks do the whole summer here!)
Start in Sturgeon Bay , learning about the history of shipping and shipbuilding at its Maritime Museum  and heading for Potawatomi State Park , and then visiting the town’s better-than-you’d-think art center and museum.
On day two, forsake the sclerotic state highway for county byways (whip out that gazetteer!) northward to Egg Harbor . No “attractions” are cartographically apparent, yet you’ll be surprised by how the short trip up the bay takes the entire morning, before unpacking at a historic inn in Fish Creek . Unwind with a stroll through the historic downtown.
Save those legs, since the bulk of day three is spent exploring the worth-a-week-itself Peninsula State Park . The sunset here is not to be missed. Continue up the coast, appreciating the vistas around Ephraim —take in some ice cream at Olson’s and visit the historic structures—before deciding where to lodge in Sister Bay .
On day four, wow yourself with a drive up and over the bluffs in Ellison Bay  and unpack that gazetteer again, for the road between here and Gills Rock  offers some outstanding side-road pulloffs to explore. Drive aboard the ferry to Washington Island  and decide between chichi gentrified or absolute rustic (or somewhere in the middle) for your abode that night. Come morning, drive to the northeast side, and hop the ferry to this author’s fave Door retreat, Rock Island State Park , easily explored as a half-day trip (but packing a backpack and tent for camping is never, ever a bad idea!).
On day six, hop the earliest ferry back to the mainland, lunch on Swedish pancakes in Rowleys Bay , and delve into the wilderness of Newport State Park . Ever so slowly, continue south and prepare to stop and strike off into estuary preserves south of Rowleys Bay. Be careful of traffic, as most travelers will be barreling to the next stop—the must-see Moonlight Bay  area, home to the most splendid of the county’s lighthouse sentinels and one of the country’s most precious ecological preserves. Baileys Harbor  makes for an excellent, unassuming retreat.
The final day’s peregrinations begin with a casual drive down the lake side to another of this author’s happy places—Whitefish Dunes State Park . The name says it all, really, those buttermilk dunes. Time left? Well, have you gone fishing yet?