My views on Trek continuity are best summed up by this quote from the Star Wars' Steve Sansweet
(director of SW fan relations) and Chris Cerasi (former Lucas Books editor) back in 2001:
"The analogy is that every piece of published Star Wars fiction is a window into the 'real' Star Wars universe. Some windows are a bit foggier than others. Some are decidedly abstract. But each contains a nugget of truth to them."
And just like that, everything fits together!