I suspect that the house dates to about 1880. I have two theories.
(a) It was a summer house for someone, literally in the middle of nowhere, on a dirt road.
(b) It may have been part of a settlement of Free Blacks on the hill, generally associated with the Thoma Jewelry Factory (formerly on the south side of Berry Street between Prospect & Summit). It was in business from sometime in the 1860's or 1870's till at least the 1890's). It's on both old atlas's. There were several worker's houses on Prospect Ave. The houses were one single family, and four or five 2-family that were later moved to the west side of Third Street at Clay St. None of those are still standing, all torn down for Quail Heights. There was also one small very small house on Hamilton Place just east of Clarendon (the only house on the entire street), several houses on the west side of DeWolfe Place (mostly still standing) and one African-American church that served this community, also still standing at Hamilton & Prospect. There was no Summit Ave south of Passaic St, and nobody lived on Summit Ave north of Passaic St. In 1880, it was all rural terrain, woods, fields, farm lots. Including DeWolf Place, there was probably a community of about 100 people, all African-American and all living on the hill. In addition to Thoma, some also employed by the Old Ladies Home on Passaic St, and some were farm laborers tilling the soil in what is now the Carver Park area. There was nobody else up there at the time, on Prospect Ave, or on the hill. The Carver Park neighborhood was mostly farmland in 1880, and the few houses were all occupied by white people. The demographics were very very different, and almost exactly reversed. Blacks on the hill (DeWolf Place and Prospect), and Whites on First St, James St, Berry St, Stanley Place, and Passaic St.
This hilltop settlement was the original black community in the central part of Hackensack, which by the 1890's began to expand east and SE and became the Carver Park community. There was a quick jump to the east block of High Street, and then everything in the whole area quickly consolidated. Meanwhile, Berry Place was bisected between Prospect and DeWolfe Place, and the Thoma Factory and workers' houses were eliminated for construction of mansions on Prospect and Summit Avenues. It's not recorded in history, but George Scudder verbally told me it was a coordinate effort on the part of realtors to make the hilltop desirable for upscale home builders. Essentially, Hackensack's black community was pushed off the hill where it originated, and pushed down to the east. The only block in common for the entire time is DeWolfe Place.
I lean towards (b). I don't believe someone would have built a summer home where there were no other summer homes nearby, no water nearby, and on the edge of a black community.