No luck getting permission - my organization has Internet access "locked down" quite a bit, so I am unable to install the Creative Cloud Desktop App. They tell me the only way I can obtain the 2017 version is to purchase it via our normal channels, which currently only offers the 2015 version of Dreamweaver.
So...back to my original question - is there a way to access the User Guide for Dreamweaver CC 2015 (2015.0 / 16.0.1)?
CC2017 is part of any paid subscription to the Creative Cloud (full subscription or single program license). The CC Desktop App is the typical method of installing any and all CC Apps you've subscribed to.
You can actually have all 5 Cloud versions (CS6, CC, CC2014, CC2015 and CC2017) installed on the same machines at the same time under a single CC subscription. They just won't run at the same time.
CC2017 is the current version, so all of the Help menu items will go to 2017 items by default. To get to 2015 items, you can do a search as Nancy suggested. As far as I know, the actual User Guide for DW is updated each release to keep pace with the program version, but the bulk of it should pertain to any CC version.
If you run into specific issues and can't find an answer, you can check out the Release Notes, What's New and Known Issue pages on Adobe's site for some direction and the forum is always here for things that aren't covered there.