I skied a couple of days at Whitewater a couple of seasons ago. We were planning on doing 2 days at Red and 1 day at Whitewater, but after skiing a day at both we chose to come back to Whitewater.
Glory Ridge is really fun, we spent most of our time in the trees to skiers right of the chairlift. We were fortunate to have tons of fresh snow, in fact we had a really difficult time getting to the ski area our first day because the road was so slippery. Locals we talked to said this was the worst they had ever seen the access road. Multiple cars were off the road and many cars turned back. We started sliding down the road at one point and were lucky that we didn't hit anything. That was the hairiest access road experience I've had! The tree runs off Glory Ridge were great: the trees were well-spaced, and the pitch went from semi-steep to very steep. Interestingly, lots of the runs get steeper towards the bottom of the run. Most of our runs ended on the cat track.
My other favorite spot on the mountain was Catch Basin into A-C shafts on the Summit side of the mountain.
I never explored Silver King but I would take
@DanoT's advice there. I'm looking at a trail map now and it sounds like they are putting a new lift up there next season that will unlock some new terrain. Super exciting!