Hi Trooper,
670 West 150th is Harlem and right on the corner of Riverside Drive.....You can see it on google maps.....there is a street view. Nice neighborhood now and then! If you follow it eastward, the street is still West 150th and it ends @ the FDR Expressway/East River.
If you pick up on the other side of the East River, East 150th St. is south of Yankee Stadium and Franz Segal Park in The Bronx. I didn't find a nowdays 670 East 150th address. But not such a nice neighborhood.... I think this is Spanish Harlem now ??
Maybe the geography will fit in somehow if you have other information.
I looked and looked in 1900 and 1910 for a John Gray and 1910, 1920, 1930 for Henry, Ellen a dau Frances (b. abt 1900 who shows in the 1901 census) and found nothing.
So like Kath & Shelly say....maybe he wanted to become lost OR the surname could likely be wrongly spelled or mis-transcribed in the US census somewhere. OR he died before 1910.
My opinion also is that the destination address could easily have been a red herring .....they didn't follow millions of people home to either The Bronx or Seattle!! and check that the friends and relatives were who they said.