JChristiansen, the records you are looking at on Ancestry were compiled by me. Patrick and Susan were the 2nd great-grandparents of my friend, Monte Calkins. I traced the family to the early 1900s in Washington, then to Dakota and Minnesota Territories based on the children's birthplaces.
The numbers are the household/family numbers. Note that people numbers 06-074-07 and 06-074-08 are missing. I can't figure out how to find them on the website, since the search is only by name. There are 12815 records in the database, and I'd have to go through it page by page to find the names of the missing persons, and they possibly were hotel staff rather than family members. I figure this Nellie is a sister of Patrick.
I found the McCarthy family in the 1880 census by looking for a Nellie and a Patrick in the same family -- and there is an Ellen the same age as Nellie. I acknowledge that this is probably the wrong family, since Patrick is listed as single. He apparently was married to Susan by 1880, unless #1 daughter Nellie and #1 son Richard were from a previous marriage -- either his or Susan's.
The other McCarthys and Petersons from that 1885 territorial census are below: McCarthy, J. 24 Painter WI Park River 05-024-12 Walsh Petersen, J. T. 35 Farmer Denmark 07-014-01 Walsh McCarthy, Geo 13 MN Grafton 06-067-24 Walsh Petersen, H. 40 Farmer Norway 31-029-19 Barnes Petersen, M. 40 Wife Norway 31-029-20 Barnes Petersen, P. 13 MN 31-029-21 Barnes Petersen, Tila 10 MN 31-029-22 Barnes Petersen, John 7 MN 31-029-23 Barnes Petersen, Olina 4 Dakota 31-029-24 Barnes Petersen, Mina 1 Dakota 31-029-25 Barnes Petersen, Anna 20 Waitress MN Jamestown 44-016-39 Stutsman Petersen, John 25 RR laborer Sweden Jamestown 44-019-40 Stutsman Petersen, Ainer 28 Carpenter Norway 53-019-31 Morton Petersen, Frank 26 Tracklayer Norway 53-030-01 Morton Petersen, John 30 Laborer Sweden 53-032-31 Morton Petersen, Ole 40 Miner Norway 53-061-01 Morton Petersen, Chas. 23 Miner Norway 53-061-03 Morton Petersen, Hans 35 Miner Norway 53-061-07 Morton Petersen, Stena 24 Servant Norway 53-061-11 Morton Petersen, Mary 65 Norway 53-064-49 Morton Petersen, Gabriel 45 Miner Norway 53-064-50 Morton
I'm also not certain the Susan Peterson living in Minnesota Territory with the Bells is the same Susan. I did trace the Bells to try to figure out whether either of them was a relative, and I don't think so.
Thank you for posting here. I'd appreciate any help you can give. I thought someone in N. Dakota might have information about the hotel.