@mattblaze At Hetch Hetchy, there are three buildings—a VIP residence, a lodge, and a house, the latter two of which are (or at least were) available for booking on a lottery system for SFDPW employees. I good friend of mine has worked for them for years, and I've had the good fortune to stay in the residence twice. It's quite a amazing to essentially have the dam and, well, the entire reservoir to one's self. Lying on one's back on the dam, and staring up at the stars on a clear night, is an experience I'll never forget.
The residence itself seems to date from O'Shaughnessy's time, and is mostly kept up with period detail, and there are copies of related historical documents, including O'Shaughnessy's original report from 1916, which I managed to scan my first time there. Photocopy of course, but tons of interesting details I'd never seen before.
Also I've always been a bit of an O'Shaughnessy fangirl; few people have individually contributed so much to what SF is today.