Have a look at LaptopsDirect for 17". They have a couple of decent ones for £350ish. Once you go above 15" they do get pricey. If a mouse is a problem, you could try her with a TrackBall from Amazon. Try one at PC World before you make the decision.
------------- Some days you are the dog,
some days you are the tree.
Early seventies and have desktop, laptop, MacBookPro, Macbook lite, and Ipad ....
All for different things.
Age makes no difference ... your physical condition obviously does ... so go for what works for your vision, fingers, postural problems etc.
There's no hard and fast best way.
Try different things in a good shop, then go for the easiest.
A day of all things motorhome and campervan. The show is held both in the main indoor arena and across the grounds. Catering, hot drinks and food options are available. Easy access to the site and free parking included. Win one of five pairs of day tickets