So back to my original question, is there a large difference in recoil and accuracy (yes I know its mostly the shooter, but I mean does one shell seem to be more inherently accurate than the other?) between the 25-06 and 7mm-08? Is one able to perform farther down range than the other?
The .25/06 is likely the flattest shooting commercially available round out there, but in practical field shooting the difference between one flat shooting round, lets say the .25/06 and another lets say the 7-08, would be difficult to exploit. If for example the .25/06 impacts 5" low at 300 and the 7-08 impacts 7" low, when both are zeroed for 200, who can make use of the 2" that you can't even see at 300 yards?
Be that as it may, the .25/06 will produce less recoil than the 7-08 in equal weight guns when both are firing bullet weights suitable for big game . . . advantage .25/06. 7mm bullets come in heavier weights than .25s, so if game larger than deer are to be contemplated the 7mm has the advantage, although a pal of mine used to kill moose and bears with his .25/06, and has no preference between the .25/06 and his son's 7X57, they both kill he says. The 7X57 is virtually a ballistic twin to the 7-08.
The importance of precision accuracy as far as I'm concerned is overrated in big game rifles. Who cares if a rifle will print 5 in half an inch at 200 when the target is a bounding 250 pound deer at 80 yards. It's irrelevant, but more importantly it is not worth paying extra for. If you happen to have an exceptionally accurate big game rifle, it is indeed a gem as we all appreciate accurate rifles, but it will harvest big game no better than a 2 minute rifle chambered for the same cartridge. What is important is that the first shot out of a cold barrel always hits the point of aim, and that is something that is more difficult to arrange in a light barrel hunting rifle. Now if the rifle is going to double as a varmint rifle accuracy is of greater importance, but a dedicated big game rifle that can shoot within a minute and a half is plenty accurate, particularly when in the field few of us can shoot under 2 minutes on demand. When it comes to off the shelf factory rifles, I doubt if there is much difference in accuracy between one chambering and another. Tikka does have a reputation for producing accurate rifles, and I think one of their rifles topped with a low power variable scope would be a good choice for your wife regardless of which cartridge you choose for her.