Main at 1.5
We launched at noon last year with the river around 1.5 and easily made it to Chuckar located at 15.9.
Concerning Alder Creek, there were some rocks showing at that level but there was a good line left of center or maybe a little more left. It may have shifted some this spring since it is a fairly new rapid. Overall not difficult.
We went left at Black Creek. It's a decent drop with a bump at the bottom and some decent waves below the bump but no real maneuvering is required. Also not too difficult.
Watch Kazak's great video for a preview of Alder Creek and maybe Black Creek, although I can't remember if that particular rapid is specifically included.