Hi there, Sara, and a warm welcome from all of us here at planDisney!
It sounds like you may have purchased a vacation package to the Disneyland Resort for your upcoming visit this Fall. How exciting! In this case, you are correct that your Travel e-Package containing admission tickets, travel itinerary, and any Magical Extras will be delivered to your linked Disney account 4 days before your arrival date. But I understand the apprehension to secure your park reservations before the week of your arrival, and your thinking is spot on because theme park reservations are subject to availability.
The good news is that you may make your theme park reservations up to 120 days in advance of your arrival date by using the official Disneyland mobile app. I called and spoke with a Cast Member who confirmed that you can start this process by linking your hotel reservation or vacation package confirmation in the "My Hotel Reservation" tab within the main menu of the app (find it by pressing the '☰' feature on the home screen). Then, you'll be prompted to enter your reservation or hotel confirmation number, your name, and the arrival date you have booked. After confirming these details, you'll be able to begin scheduling your theme park reservations! Since you are currently more than 120 days away from your arrival date, this page will also display the date on which you can begin to make your park reservations, corresponding to your visit. If you run into any challenges, please don't hesitate to reach out to Guest Services and a Cast Member can help you navigate any issues directly.
I hope these suggestions have been helpful to you, Sara! You are visiting during an absolutely spellbinding season as Disneyland Resort will be celebrating Halloween Time during the months of September and October. Don't miss my favorite photo opp with the Giant Mickey pumpkin on Main Street, U.S.A., and enjoy other frights and delights highlighted during this special seasonal event! If you need any other recommendations, or if you have any follow-up questions, please don't hesitate to reach out via planDisney again!
Wishing you Wondrous Journeys,
Tishra