With the arrival of WWII most Roma in America went to California and other West Coast locations to do light metal work ~ mostly in the aircraft industry.
They've subsequently lost their 'culture'. Nothing like regular, steady employment to put an end to life on the road.
There's an entirely different group ~ the Travelers ~ who are not Roma. They are not ethnically the same, but a handful of Roma did enter UK at about the same time the Enclosure laws were putting tens of thousands of Irish and Scottish tenant farmers on the road.
Those Roma quickly expanded their reach into UK society and pocketbooks by "hiring on" native Irish and Scottish people.
Those are the folks your father feared in Minnesota.
The travelers where Irish
Interesting. Thanks.