Hello there, Ryan! Welcome to planDisney. I know there are a lot of details to plan for a Disneyland Resort visit and I don't blame you for wanting to get started soon.
Currently,
theme park ticket reservations can be made 120 days out from the date of your visit. If you are going to be visiting multiple days you will have to either book each day as the days open up on the calendar or wait until they are all available. This means you have a few weeks before you can get started if you are wanting to wait to purchase tickets separately. However, I have a suggestion!
Since you are wanting to stay at Disney's Grand Californian Hotel & Spa, why not look into a
Disneyland Resort Hotel Package? This will allow you to go ahead and bundle your theme park tickets and hotel accommodations. With a package, your eTickets will link to your account 4 days before your arrival, but you will be given a link and instructions to make your theme park tickets as soon as your days open up on the calendar. When you purchase a package, you also have the flexibility to cancel and receive a full refund as long as you cancel at least 5 days before your scheduled arrival.
Ryan, I hope this helps you figure out your next steps to start planning. Be sure to stop by again with any other questions you have along the way!
Carrie