A.,
My son recently had a 4th birthday party with friends of varying ages as well--his theme was Batman but the games/activities could be made for Princess.
I made cutout sugar cookies of Bats, in your case you could get a crown cookie cutter or maybe there is a princess cutter available. All the kids were given edible food markers and small tubes of colored gel to decorate. This was a huge hit with all of them and the parents and they got to eat the decorated cookie too.
We have a bean bag game with animals on the holders for which you throw the bag through so I just enlarged some photos of the superheroes at Kinko's, laminated and taped them onto the boards. The kids thought they were cool and my son kept the cutout guys for himself afterward. Plus, bean bag toss is easy for kids of all ages.
You could probably get a princess poster or colorbook to use pictures from.
A.
A little about me: work out of home office Mom to a charming 4 yr old boy and a darling girl who turns 1 today!