If you let them know you're interested in seeing the sanctuary, someone will give you a tour. Just don't go Friday evening as that's when the main service happens and the sanctuary will be in use. They're open on Saturdays and someone is available to give tours. Note if you don't know this but, like for many big synagogues, there is security you will pass through. It's a quick scan and they'll check your bag so just you know, don't have a pocketknife or something. Other than that, they're very friendly and welcoming.
They have daily tours. Ask when inside if picture taking is allowed.
Absolutely not! We found it to be very progressive. We are not Jewish and we did a lovely tour during our visit to NYC in January.
Thanks! Your answer is awaiting moderation.