Every Apple Watch since the Series 2 has built-in GPS, even the models without cellular connectivity.
I have a non-cellular Series 6. It has 32 GB of internal storage, so I sync music and podcasts to it and use it as my only device when running. I even have an app (WorkOutDoors) that supports offline maps and routes, so I could use it to follow a route while running without my iPhone if I wanted to. Once I get home, it automatically syncs all of my exercise data with my iPhone.
So, the short answer is yes!
I have a non-cellular Series 6. It has 32 GB of internal storage, so I sync music and podcasts to it and use it as my only device when running. I even have an app (WorkOutDoors) that supports offline maps and routes, so I could use it to follow a route while running without my iPhone if I wanted to. Once I get home, it automatically syncs all of my exercise data with my iPhone.
So, the short answer is yes!