Claudia Dietrich and Ross Lloyd boarded a bus bound for the hottest tourist spot in Chicago’s River North neighbourhood. While their guide rattled off Chicago trivia, the couple snapped photos from every angle — even the alley. They weren’t deterred by the winding line out the front door. “This is something that brought us to Chicago, there’s no doubt about that,” said Dietrich, a 72-year-old Milwaukee resident. Their destination? Mr. Beef, the no-frills sandwich joint featured on Hulu’s smash hit, “The Bear.” It’s the first stop on their guided food tour inspired by the series. A traditional …