Okay, after looking at all my pants and shorts options for my Riley I decided to start from scratch and draft a pants pattern. Coni Amaden-Crawford has a wonderful book Pattern making Made Easy. It's a cookbook like approach to pattern drafting. Riley has such a unique body type, she is 9 years old and has a very tall heavy body frame. Children's plus size patterns are quite large on her, and adult patterns have the wrong proportion. Here is a picture of the pants back. Here is a picture of the muslin. The only modification I made from the instructions was to use a 5 1/2" hip line measurement instead of the 4" for kids or the 7" for adults.
Here is a picture of the finished pants.