Hi, Lisa!
Yes, all registered Guests of the three Disneyland Resort Hotels are granted early admission to select attractions, dining locations and shops in either Disneyland Park or Disney California Adventure Park one hour before it opens to the general public.
The theme park offering an Early Magic Hour varies depending on the day. The current schedule grants Guests early admission to
Disneyland Park on Tuesdays, Thursdays and Saturdays and to
Disney California Adventure Park (including access to Cars Land) on Mondays, Wednesdays, Fridays and Sundays. So, keep in mind that if you’re only staying for one night and want to take advantage of the Early Magic Hour specifically to ride Radiator Springs Racers at Cars Land, you’ll need to plan your visit according to that schedule.
To make the most of the Early Magic Hour experience and ensure that you’ll be one of the first in line for the attraction of your choice, be sure to arrive at least one hour and 15 minutes prior to the regular park opening. Each member of your group must have a valid theme park ticket and active hotel room key card for admission.
I hope this helps, Lisa. Please let me know if you have any other questions as you continue to plan!
Wishing you magic,
Courtney