Navigation and maps is super clunky.
Basically, you can download offline maps to your watch through maps now. But, there is no current integration with the workouts app that I have found yet. They work as two different independent silo'd apps. You can create your own routes and save them in a folder in maps called "Routes". Once you click on them, it goes into the typical Apple Maps navigation experience as if you were walking to a location, any time before. It's fine, but nothing new, and certainly not integrated.
Apple Maps team doesn't seem to be talking to Apple Workouts team.
There is lots of room for improvement at this point.
But, we do have offline maps. So that is a start! Some details are just plain wrong, like elevations of routes, but I am sure those things will be fixed in time.