Tom,
I'd say walking it, as I've never actually hit on shot on the course.
When I did walk around there, it had this very gentle feel to it. I expected a more abrupt presentation of hazards and with the green contours. It was almost as if the course was sleeping, and only woke up when a bad shot was struck. The greens are fast, but not unforgiving, and certainly not impossible. Each hole has a back door to par or even better.
Some of the shots there seem to broach my comfort level too. Some of the holes on the front have funny angles that you don't normally deal with everyday. Oakmont subtly takes you away from your comfort zone, and I'd imagine it would continue to do so replay after replay.
You open with two gentle, but different Par 4s, the greens slope away from you, you're shocked that you can't fly it all the way to the hole and that you have to trust the slope to take it to the hole. They're short and manageable, but throw you off a bit.
Then comes the church pews, the trenches, the long par three 8th, the huge green at nine... all test your execution and all throwing you off a little bit, not wowing you like Pebble, bust just unsettling you.
The back nine is the more strategic of the nines. 12, one of the few true three shotters left in the game, lets you choose one of several different ways to its green. 17, lets you go for broke off the tee, and 18 just gives you a plethora of attacking options, depending on your game.