This doesn't satisfy the urban piece of your request so much (I suppose you could count Michigan City or Benton Harbor). Its also pretty obvious, but you might consider anchoring a trip around Warren Dunes (Sawyer, Michigan). I can't more highly recommend the charmingly rustic (+private beach!)
Lakeside Inn. I don't have a slam dunk "New American" dinner rec., but you could do a lot worse than BBQ and beers at Greenbush, which I think is putting out some of the best brew-pub grub anywhere these days. And there are plenty of other locally-focused artisanally- inclined eateries in the area- Luisa's for breakfast, Whistle Stop for sandwiches. Even GNR, Stop 50, is not that far from the area.
I grew up summering in this neck of the woods, though I find the area unrivaled for laid back beach getaways and a surprisingly evolving food scene.
Warren Dunes State Park
12032 Red Arrow Hwy. Sawyer, MI 49125
Lakeside Inn
15251 Lakeshore Rd, Lakeside, MI 49116
(269) 469-0600
Greenbush Brewery
5885 Sawyer Rd, Sawyer, MI 49125
(269) 405-1076
Luisa's Cafe
13698 Red Arrow Hwy, Harbert, MI 49115
(269) 469-9037
Whistle Stop Grocery
15700 Red Arrow Hwy, Union Pier, MI 49129
(269) 469-6700
Stop 50
500 South El Portal Dr, Michiana Shores, IN 46360
(219) 879-8777