Keystone is my home mountain. It's pretty well groomed, which can be a problem if you're trying to get better at choppy terrain. You can find it on the backside, but on the front check out Sante Fe off of Spring Dipper on the far right of the frontside. It was ungroomed as of last Thursday. Also, they keep moguls along the side of Flying Dutchman.
Wait till it snows a foot, and the whole mountain is chopped out after like ten minutes lol. Plenty to practice on then. Unfortunately, it's been really low tide lately. We could really use a dump or two.
There's literally a ton of tree riding at Keystone, but they're pretty tightly spaced. I'd stay out of there even if the snow conditions you seek seem to be in there.