Ahoy Brooke!
Thanks for sailing by the Disney Parks Moms Panel. It looks like you are about to embark on quite the adventure today! I hope this answer reaches you in time.
You have a whole new world of options for Princess costumes at Disneyland Resort. I know you were concerned about getting to
Downtown Disney District, but it is on Resort property and less than a five-minute walk from the main entrances to the Parks. At Downtown Disney District, you have
World of Disney, which offers a whole new world of princess possibilities! Also, right outside of
Bibbidi Bobbidi Boutique in Fantasyland is both The Mad Hatter and Royal Reception, two shops that sell royal-themed merchandise.
If you feel pressed for time (and make sure to allow plenty of time to get to your ship, a cruise waits for no-one!), no worries! There are
fantastic merchandise shops onboard the
Disney Wonder (I'm assuming this is your ship with your itinerary) that
sell majestic royal clothing.
Bibbidi Bobbidi Boutique is also on your boat, so your girl can have a royal (or pirate, or holiday-themed) transformation on top of her costume! Regardless, you have plenty of options on board to indulge her fantasy.
Brooke, I wish you a magical sailing!
Rayna