Thanks so far for the feedback. Sounds like this Hutchinson Expy / Sawmill Pkwy area would be the main bottleneck, then, for this commute from NYC.
Ultimately, I know that HPN would be my first choice. However, to add options in the event of IRROPS, it's OK if I have to budget an extra 1.5 hrs for the further commute to airports with more arrival options.