Actually the answer about more info about Sophie Hassan might be found in diligent search of records of the Kings County Assylum
http://www.lioddities.com/Asylums/Kings_Park/history.htm
If anyone in NY could do this and find a record of her admittance and discharge or whether she was discharged at all that would be a nice find.
Census and marital records in the area might reveal something too.
-Eduardo
PS: It was probably constructed in the 1890s as some of the older buildings are listed from that period. No wards are listed from that period which suggests that the original ward may have been torn down. Or maybe as you suggest, Harrison got it wrong and the period is really during the early Rutherford period but the situation seems more like something that would happen to Russell.
Here is a better article: http://en.wikipedia.org/wiki/Kings_Park_Psychiatric_Center PPS: the name change from Kings County Asylum as referred to by Harrison to King Park State Hospital in 1895 when the state took over suggests that this affair with Sophie Hassan occurred prior to 1895 and thus does place it squarely in Russell's period and would seem to fit very well the culture of that time and with the young Russell's appeal to such groupies.