I checked the Disney website for you, here is what it said:
The restaurants at all 3 Hotels of the Disneyland Resort are open to everyone.
However, all other services at the Disneyland Hotel, Disney's Paradise Pier Hotel and Disney's Grand Californian Hotel & Spa are exclusive to the hotel a Guest is staying at with the following exceptions:
- If there is a closure or other situation whereby a Guest or Guests have been granted access to services at hotels not specific to where they are staying, they will be duly notified of the temporary policy change.
- Guests of the Disneyland Hotel and Disney's Paradise Pier Hotel may use the massage services and Pinocchio's Workshop (children activities center) at Disney's Grand Californian Hotel & Spa for an additional fee. Advanced reservations are required.
- Guests of all 3 Hotels of the Disneyland Resort can enter and re-enter the Resort using the exclusive entrance into and exit from Disney California Adventure Park with valid theme park admission.
If you have any more FAQ questions, you can check here:
http://disneyland.disney.go.com/faq/hotels/