The racial and social attitudes on the program reflect its 1970s filming as opposed to its 1880s setting. This is especially noticeable when the series dealt with issues regarding women, minorities and immigrants.
The majority of the men on the series were clean shaven, which not only doesn't match the historical photos of the era, it doesn't match the fashion styles of the time. Few adult men didn't have some form of facial hair and many had full beards.
Despite being prairie women, it's clear, especially during later seasons that all of the female characters have hairdos which were professionally done, as well as manicured nails. Neither of these were "in fashion" for poor women in the 1880's Midwestern US.
The real Charles Ingalls had a beard which he wore his entire adult life. Michael Landon, the actor who portrayed him in the series, was always clean shaven or had some slight stubble for the run of the show.
After the episode where Nellie's restaurant name is changed to 'Caroline's', there are times afterward when the name on the window changes from 'Caroline's' back to 'Nellie's' and back again. Obviously there is stock footage thrown in from time to time.
The time line in Season 1 is not accurate. All the shows preceding the Christmas one (the family's first Christmas in Walnut Grove) would have taken way more than a year to unfold. In particular, Caroline becoming pregnant, going through nine months of pregnancy, and then Baby Charles living a few months before he died, couldn't have all transpired prior to their first Christmas at Plum Creek.
In part one of Gold Country, even though there has been continuous torrential rain for months, there is also blazing sunshine and clear blue skies visible in several shots in Walnut Grove, despite the rain.
None of the areas shown in the television correspond with the range of Midwestern states where the Ingalls lived during Laura's childhood. Most notably many of the areas where they lived were green prairies and rollings tree covered low hills. The series, even the intro, were clearly filmed in an area which experienced an arid climate, likely near and around Central and Southern California.
There is no episode or part of one to show how the blind school Adam, Mary, and Hester Sue ran was taken over by someone else. This, however, will later be spoken about by Hester Sue in "Second Chance."
Featured prominently in at least two episodes ("The Monster of Walnut Grove" and "The Music Box"), restless tree branches are seen and heard immediately outside the front upstairs window, next to the girls' bed. But at no point in the show did any such tree ever exist that close to the house.