I'd go with a .243 simply because I've owned one since 1980 and killed over 300 deer with it...My brother has a 7mm-08, it kills them as well, little difference on how far they run after a lung shot...
Depending upon your wife's size, a Remington youth might fit the bill, a Model 7 or even a regular size 700....I've got a buddy that is only about 5'6" and a regular 700 fits him fine...
Another advantage to a .243 is 100gr Remington CoreLokts work as well as any bullet out there...You can catch them on sale for $15-18 a box whereas 7mm-08 bullets are as scarce as hen's teeth and CoreLokts in that caliber run almost $30 a box...Practically any place that sells ammo has .243 ammo...