Hello Zell
Its been some time since we did the cruise up the door county. We stopped at sand bay for a swim as the water is shallow and usually warmer. You'll see the party area as it usually has quite a few boats beached. Plenty of sights to see in Sturgeon Bay. The shipyards, resorts, Marinas etc. There was a resort called The Moorings that had a good fish boil and live music that was a lot of fun. Moving further north be sure to dock up at any and/or all of the small ports , Egg Harbor, Fish Creek, Sister bay and Elllison Bay etc. Many shops easily walkable from the piers. Another good spot to hang out is Peninsula State Park by Eagle Harbor, when we were there we saw boats from all over the Great Lakes region. On Washington Island there's Detroit Harbor. On the east side of Door County is Cave Point and Whitefish Dunes State Park. You can then go through the Ship Canal and back to Sturgeon Bay.
Good Luck
Have a safe cruise
TK