An adventourous intermediate can handle most of the non treed terrain at the boat.
Intermediate Powder Day:
Take to Gondola up and take Rudi's Run to Lightning down to the Storm Peak Express.
Traverse over to High Noon and down to the Sundown Lift and do laps going further right into the O'clocks. And if your still comfortable try Storm Peak Face.
Intro To the Trees.
If Wally World(Sunshine Area), the trees off of Tomahawk & Quickdraw off a nice intro to tree skiing. Also if your comforatble try the trees in Big Meadow and between Calf Roper and Meadow Lane. Triangle 3 is the next progression I think before you hit the Closet & Shadows area.
If Morning Side is open ther are a bunch of short nice pitches in there
Of course this is all my opinion, I am sure you'll get others.
If you have skied Hunter, most of the Blacks are on par with Hellgate and the Hunter West runs.