The biggest problem I've run into with the street bikes with weak front suspensions (RST falls into that group) is that they "mush" out on you and kill any ability to accellerate well on the bike.
Basically if you try to get agressive on the bike the front forks just dip down and prevent you from getting a good momentum built up. They'll also bottom out easy and are there more for marketing than anything.
But your daughter probably isn't pushing 200 pounds and really beating the crap out of the bike like I did.
I had a GT hybrid that was pretty much identical component wise to the Trek. It was comfy and worked for riding streets and paved trails, but the front RST suspension was more for marketing than any function. It just was too soft and didn't have enough travel.