Sunday, March 5, 1882
The Milwaukee Sentinel, Mar 6, 1882, 5
Water and Oneida (now 144 E. Wells) Streets, Milwaukee, WI
 The University of Wisconsin-Madison Libraries web site erroneously gives the date of the fire as 1893
Grand Opera House and City Hall (right), Milwaukee, WI
Source: Milwaukee Public Library
West Water and Second (now Plankinton) Streets, Milwaukee, WI 
 Later address was 123 Grand Ave., now 161 W Wisconsin Ave.
"In fact, the Milwaukee Sentinel, in an interview with Wilde that was conducted the morning of his appearance (he had arrived at 11:30 p.m. the night before and checked into the Plankinton House hotel...) couldn't help but poke some fun."
"he stayed at the old Plankinton House..."
While these are not primary sources in themselves, they are the corroborative reporting of a primary source, and there is no reason to doubt them.
The Plankinton House Hotel extended, as it looked at the time of Wilde's stay in Milwaukee.
The original Plankinton House Hotel in Milwaukee.