Overall, the guide looks really great. I only noticed a few minor details that could be clarified:
This is mentioned in the "Ins and Outs of the Center Space" but perhaps it would be worth including in the "Interacting with Patrons at the Rumsey Map Center" too: share with patrons when they arrive that the bathroom requires a key and point out where in the center it's located, along with where water fountains are (since we are asking them to not bring drinks in).
There is a minor typo on the "Finding Maps" page in the "Viewing Material In Person" section: the sentence starting with "For someone to view Rumsey Center materials in-person... 'desired'".
In the list of "Common questions" in "Answering the Phone at the Rumsey Center", it would be helpful to explicitly mention that there are sheets of paper included in the binder and on the table beside it ("Hi, thank you for calling the DRMC...") to fill out if Niles/other staff are not accessible at the moment and information needs to be passed along.
Overall, the guide looks really great. I only noticed a few minor details that could be clarified: