There are a number of character meals outside the parks, a breakfast would be the least costly. We did a character breakfast late morning so it served as brunch and lasted us well past the dinner hour.
Chef Mickey's at the Contemporary (Mickey, Minnie, Goofy, Pluto, Donald)
1900 Park Fare at the Grand Floridian (Pooh and Friends, Mad Hatter)
'Ohana at the Polynesian (Lilo and Stitch, not sure about Mickey)
Cape May at the Beach Club (Goofy, Chip, Dale and not sure who else)
The one Princess Meal outside the park is Dinner at 1900 Park Fare. She'd get to meet Cinderella and the step family at this meal. We did this meal years ago with a 5yo princess when we stayed off site, it was absolutely magical for her and she was all dressed in her princess attire (brought from home). We haven't been to the new format of the meal, but so long as Cinderella is there I think most 5yo Princesses would be content. My guess this meal will cost about $30 per adult and $15 per child.
Bang for the buck I'd choose Chef Mickey's breakfast. Princess experience you'd need to choose 1900 Park Fare.
There is also tea at the Grand Floridian. I don't have first hand experience, but that could be another option. Hopefully someone can help with info on those.