They are quite accommodating to their clients. So I recommend you speak to them directly and preferably in advance.
Call the Sarah
This facility follows the same systems/times for checking in/out as the hotel industry... Checking in 3pm and out by Noon; however, should you need to change this (checking in earlier or checking out later), all you need to do is call! Cheers.
I'm not sure what time check in/out is because it has been quite some time since I stayed there; and it was in an academic capacity with a group of students. I recommend that you contact Tarrytown House directly to receive accurate information. I do recall it being a very nice hotel...
Thanks! Your answer is awaiting moderation.