Rice flour ok sub for AP or need to add other ingredients?
According to the Joy of Baking, you can substitute rice flour for most of the quantity of AP flour in a baking recipe, but not all of it. See here for more info: http://www.joyofbaking.com/IngredientSubstitution.html
If you're trying to make something gluten-free by subbing rice flour, you'll need to add other ingredients. This combination works very well for me for most baked goods:
1 cup any gluten-free flour (or rice flour)
1 cup sweet rice flour
2-4 Tbls tapioca flour
Gluten-free Girl also has some good information on her blog. She has very good advice on how to make something gluten-free and still whole grain. (Look for it near the middle of this page in the link.)