Just back from 2 nights and three days at Disney's Grand Californian. Loved the hotel almost as much as much as the Ahwahnee in Yosemite. Much to our surprise, it is not a knock off. Rather a very beautiful representation. We especially liked the fact that it was not just more disney fun. It was a bit of a relief to escape to the Grand Californian in the afternoon. We really enjoyed the pools and staff was excellent.
We checked in about 4:30 on a Sunday afternoon. We asked nicely and were upgraded to a view room. We were in Room 4322, 4th floor with a view of the pool and an adequate sized balcony. We could also see the ferris wheel in California Adventures, which was so pretty to watch change colors at night. Plus a bit of the World of Colors show. This room was extremely convenient location: close to the elevator, above the Storytellers Cafe, and close to the gate to California Adventure. I gave the hotel 4 stars instead of 5 because the bunk bed mattresses were very uncomfortable and the pillows hard.
Regarding the Costco Package - the only thing I suggest is to fully understand the meal voucher before you use it. We received three vouchers, two adults vouchers at $43 value each and a child at $22 value. We used one voucher for the first breakfast when we ordered from the menu rather than the buffet. The next day we used the other two and all three went to the buffet. Each meal fit the $ value of the voucher. However, on the second day the waiter said the policy had changed and you could only use one voucher per person. Turns out we had premium vouchers, but were using them at the less expensive restaurants. Leaving money unspent on the voucher by only using one per person.