I played it in November and didn't think it was crazy difficult. There is certainly lots of potential to lose balls if you spray it, but the corridors are pretty wide, so to lose a ball, you REALLY have to hit a bad shot. Again, I played in November, so maybe the rough was down for the winter. I didn't find the walk terrible, a couple of decent walks between holes and one big trip up a hill that they drive you up, but I've had harder walks.
Overall a great experience, one of the best Nicklaus courses I've played or seen. I played with my brother in law who lives in the Bay Area and plays in a lot of amateur tournaments and he says its in his top 5 in all of NorCal, which I thought high praise as he's pretty well traveled.