Hi Midge,
A different twist on the "bring a meal every day" idea (which is great--folks did it for our second child) is to ask guests to bring a frozen meal item, e.g. soup, chili, casserole, stroganoff meat, spaghetti sauce etc. and fill the family's freezer. Could be store-bought also if people don't like to cook or don't have time.
Re the princess theme, if you have children attending the shower, you could make them crowns and they could be princes/princesses. Or let them decorate their own crowns--keep them occupied! Scepters, anyone?
If you feel moved to make napkin rings, they could be crowns too.
You could have "royal purple" as a color for tablecloth, napkins etc.
Don't worry, whatever you do will be fine--the main thing is getting together. Take photos of the event and give copies to your daughter for the baby book.
Have fun!
K. Z.