UN Headquarters (NYC): Entry procedures, internal arrangements?

[penta]

OK, so, for a completely separate RP than my last few posts (still set in an AU of the "Ender's Game" universe, but still), the characters are going to be going to UN Headquarters in New York. Basic theme is that because they're superintelligent and multilingual, they're being loaned by the International Fleet for a bit as (to quote a previous post in this DWRP PSL) "...a translator, protocol monkey, interpreter, and escort to VIPs at the UN" - basically, since they're both on Earth for reasons, and they both live in or near NYC, this is how they earn additional funtime on Earth until everybody decides it's time to send them to their next stop, ICly.

Questions I have re UN Headquarters:

1. What exactly is security like? I've never been to the UN IRL, so I don't even know the basics like "Do they make you have special badges" or "Are the security people armed usually". Not looking for deep details, just what someone working there wou

2. When heads of state (like POTUS for example) come to visit the UN, do they bring their own translators/interpreters, or does the UN provide em?

3. New York gets *cold* in the winter (I know, I live in New Jersey), and the UN campus being right along the East River...Yeah I prefer not to think about what the wind does. Does the UN campus have underground tunnels for movement of people on those stupid cold (or, in the summer, stupid hot) days, or is movement between buildings all via the outdoors?

4. Bonus question, maybe someone here's worked at the UN: How good, or bad, are the staff cafeterias at the UN, and how expensive are they (compared to eating out in NYC usually...)?

Sources tried: Google ("UN Headquarters" and following links from there), UN.org, Wikipedia on UN Headquarters.