Hello, Guadalupe! Thanks for returning to the Disney Parks Moms Panel with another great question!
I checked with a Cast Member, and you can certainly take the shuttles from the Toy Story
parking lot to the Disneyland Resort area. In fact, that sounds like a really resourceful idea to me! Remember that when you arrive at the parks, you will need to go through a security checkpoint that includes searching any bags and you will have to go through a metal detector.
Will you be visiting the Disneyland Resort for three days or longer? If so, don't forget to take full advantage of your one
Magic Morning at Disneyland Park on either a Tuesday, Thursday, or Saturday. During this extra hour, you can enjoy many of the attractions in Tomorrowland and Fantasyland with typically low wait times. Even though early entry is only for Guests with a three-day or longer ticket and for Guests of the Disneyland Resort Hotels, I recommend arriving early to the gates. Keep in mind that the Toy Story lot may open only one hour before the general theme park opening time (not the Magic Morning time), so if you intend to take advantage of Magic Morning, you may want to walk to the parks that morning so you don't miss out on any fun!
I hope this helps. Have a fabulous visit to the Happiest Place on Earth!
-Linda M.