mrsboz,
I just did a very successful Princess party. My DD turned 4 and her guests were boys and girls from 3-5.
I printed out prince and princess coloring pages and had that set out on our coffee table.
On another table I had crown making projects. I went to Burger King and got 15 crowns and spraypainted them gold. Then the kids glued on gems and sequins. I got the stick on earrings to use as gems.
On the last table I had pink and blue paper bags that the kids decorated with princess stickers. They used these bags to collect goodies from the princess pinata. The pinata was filled with rings, bracelets, necklaces, toy soldiers, cars and candy.
After the pinata, I had a big bowl filled with sand and plastic jewels and gold coins and shells. Easch guest got to reach in and pull out their treasure. I told them that Ariel dropped off some magical sand from her beach.
I am sure your princess is going to have a great day!