Once located on display at Bandana Square behind GTW 0-8-0 8327 and supposedly moved to Gopher State Railway Museum in New Prague, MN. Not sure how active this organization is, nor whether the car is there.

I think this car has been in New Prague for at least a couple years. I hope the shelter construction campaign will succeed in protecting their nice collection.
http://www.gsrm.org/roster_of_equipment

https://www.facebook.com/gopherstaterailwaymuseum/

I follow their facebook, they are a plucky little group located along the ex-M&STL, now UP west of St. Paul, they have 1/3 of a mile of track and an operating SW1 from a power plant. I looked through the photos on their facebook page and didn't see the GN RPO, I know they have offsite storage with among other things a CB&Q lightweight coach and a NP S4 that keeps getting hit by vandals. They do have this car, obviously converted to a cottage, which as they describe is a nightmare on the outside but very intact on the inside, it was GN founder James J. Hill's 1880 Pullman office car, originally built for the St Paul, Minneapolis & Manitoba Railway and named "Manitoba".