I have called three times in the last week and I've gotten different people each time on the phone just to be sure it wasn't one persons opinion of how it was going to work, and they all said the same thing;
Disneyland will be open normal hours during the Halloween party but if you don't have the ticket to the Halloween Party you can't go in to California Adventure.
So if you have a park hopper and the Halloween ticket or a Disneyland only ticket and the Halloween party ticket, then you could still go from park to park during the party. Please let me know if anyone knows any difference. Thank You
I apologize if I have used any incorrect names for lands or parties, no offense was intended.