280 cal or 7mm mauser REM mountain rifle. Both are very light and have the ability to be used at long ranges out in WY or MT, as well as in the thick of N.. MN. Either of these guns would be a great first gun and you wouldnt need to buy her another. Plus if she loses interest, then you get a great deal.

Find a Remington 700 or 710 in 270. They're both excellent rifles. If you look around you should be able to find one for under $500. A .308 wouldn't be a bad choice either.