Hello Robin!
Lovely seeing all your questions for planDisney! We love helping you create magical memories with your grandkids!
Many times when visiting Walt Disney World Resort I purchase my tickets and room separately. It is totally fine!
Early Theme Park Entry is linked to your Resort Reservation, not your tickets. While you do need a valid admission ticket to enter the Parks the Cast Members at the Early Theme Park Entry areas will ask for you to tap in with your MagicBand or ticket or show your reservation on your phone. I like to sometimes just show the reservation from the
My Disney Experience Mobile App. When entering the Parks make sure to look for signage guiding Disney Resort guests to the Early Theme Park entry entrance. It could be after the actual ticket scanning area and if you are lost just ask a friendly Cast Member for some guidance.
Magic Kingdom Park is unlike other Parks during Early Theme Park entry in that only two lands are open during these early hours. They are Tomorrowland and Fantasyland. Fantasyland has so many great rides that are perfect to enjoy with little ones that have
no height requirements. I have seen families with small babies enjoy
Peter Pan's Flight with ease as it is a gentle ride to Neverland. This attraction gets busy very quickly so if this is on your list I would make this a priority to enjoy early on in your day.
I hope this helps and you can travel with your family to many magical places!
Happy Planning!
-Nimmy