The Historic House Trust of New York City produced a “Cultural Landscape Survey” of Van Cortlandt Park in 2003 and included this image:
I’ll have to see if I can find a better copy and if anyone can explain the perspective of the photo. It is worth noting that Van Cortlandt wasn’t the only large farm in the area at that time. Just to the north of today’s Van Cortlandt Park was Boss Tweed’s “Valley Farm,” which stretched along Tibbetts Brook from Highland Ave (today’s McLean Ave) to beyond Yonkers Ave. The NYPL has a map of that one.