As you've noticed there's no Baseline class, so you'll have to go to the database to retrieve that information.
Each baseline has a row in t_document with DocType 'Baseline' and ElementType 'Package'. The GUID you receive from GetBaselines() should be matched against DocID.
DocName holds the name the package had when the baseline was taken, while ElementID has the GUID of the element/package. Version and Notes contain what you'd expect, and the date and time are in DocDate.