I think the best and cleanest solution is to leave both the PIP and the GSP in usasf. This allows users to mark them clinched as connected routes, and can even be philosophically justified as "well, neither of those are purely New York parkways".
Indeed, the Palisades is specifically an Interstate parkway (says it in the name!), and the Garden State Parkway fundamentally is a New Jersey thing, it just happens to have an extension into New York at its northern end.
Also FWIW, neither is an NYSDOT maintained roadway in spite of their reference route numbers - PIP, as mentioned above, is maintained by a separate park commission, and the GSP extension is part of the New York State Thruway system (it even allows trucks between the Thruway mainline and the one NY exit).