location (if you're local), close to St. Louis
small, crowded, no real consideration of visitors
Three-year season pass holder here. This is my home hill so I feel I should review it for others.
Hidden Valley is a fine place to learn to ski/ride. Far cheaper and less intimidating than going to a big mountain. If this is your first year on snow, it's a viable, economical choice in part because the weekend offers late-night access.
However. Once you surpass that, I wouldn't recommend making this your vacation spot. Local kids act like they own the place, far more than in a mountain town like Keystone or Breck. They ride like you're trespassing on their hill, and that feeling doesn't diminish much even when you're there every weekend lapping the park with them.
The worst part is the way this place is run by management. The bigger terrain park (where I ride as well) is placed on one of the most accessible blue hills, one that would allow a LOT of riders and skiers down it compared to the maybe ten or twenty snowboarders in that park on weekends. It's a poor park at that with very icy landing zones that are almost impossible to set down on. Four years ago the big park was constructed on the back run, a wider run with room for park riders and regular riders; I'm not sure why they don't do that but it seems like very poor operations.
Additionally, the resort shuts down the *other* front side run parallel to the big park for NASTAR racing. This occurs from about 12:30pm to 3pm every Saturday and Sunday and serves -- on average -- about ten people. On the busiest days the resort shuts down one of the two runs to the lodge (the other is the big park) so ten or so people can race. I've been there nearly every weekend the last three seasons and I've never seen more than fifteen people in line to race. Yes, I actually count every week because it infuriates me the resort obliges these handful of people instead of the many, many people who come there and are limited to two blue runs instead of four. As a season pass holder, it's maddening to be shoved off two of the best runs; if I were on vacation, I'd really be upset about this disregard for the majority of visitors.
If you have kids who are learning or you're just looking to play in the snow -- and Hidden Valley is fairly local to you -- then this is probably a reasonable place to learn. You're never more than a few hundred feet from the lodge, the parking lot or each other. But if you already know how to ski/board and you're looking for a place where you can have a good weekend in the snow, I'd think very hard about visiting a resort that caters less to a handful of locals and more to the vacationers who no doubt keep this place open.