The only 2 hotels that I know of that dont have keyed elevator are Marriott Copley Place and the Royal Sonesta (Cambridge). The Marriott has a very large lobby that is integrated with the copley Mall. so you can come and go with 0 interaction with the front desk. its a popular convention spot and located downtown, accessible by public transit, so can occasionally get expensive for its room quality. The Royal Sonesta, is closee to downtown but being in Cambridge is less busy. It does have relatively cheap suites and great views of the Charles and Boston skyline (if you get a city view room). I have seen providers in both these hotels, with no issues. I was at the Marriott 2 years back, and the Marlowe like 10 yrs back so its possible things might have changed there, but I would think the elevators are still keyless.
You could also ask Tyler what hotels she likes, since she is local. There are lots of botique places around the city, but they usually have small lobbies and hard to come and go incognito.
