The CVA BuckHorn is a really good gun. i have scoped and sighted in a lot of them for local hunters. The stock of the BuckHorn is much more rigid that the stock of the gun it replaced; the StagHorn.
Start the young lady out by loading 70 grains of Pyrodex and the excellent 240 grain XTP bullet. That load produces very little recoil. Increase the powder charge to 80 grains and then to 90 grains if she still has no problems with recoil. 80 or 90 grains of Pyrodex and the 240 grain XTP bullet is a good deer load.
i hope that your daughter bags a big deer.