Parking in that area is terrible at all much less for the whole weekend. If you don’t want to take the bus it would be cheaper to take a cab than to park a car for two days.
There’s free parking under the viaduct (the ferry “hold” lanes next to Marginal/Alaska) and more free parking along Marginal/Alaska. There are some parking restrictions, but much of it is free 24/7. That said, it’s not safe, I see many cars down there that have broken windows or window glass left along the roadway. You are better off to take a bus or take a cab to the station.
