re: Please help with PC purchase

SSD is the most important thing. Based on what you've said (limited local storage because of DropBox), 256GB is sufficient; she's not installing Skyrim or ElderScrolls Online, etc.

8GB of RAM is sufficient too, but take 16GB if the price is palatable. If she often has 50+ browser tabs open at once, 16 may be the preferred route, but I am pretty sure that's not happening in her case.

Generation of Intel/AMD is totally irrelevant given the use case. In her case, even an Intel i3 (which is a model, not a generation) would be fine.

And also consider it may open up a ton more options just to buy her a big monitor for sub $200, and ignore the screen size requirement. 17" is hefty for a laptop, and will often push you into gaming (ie, more expensive laptops.) Since she does bookkeeping, having a $200 28" wide monitor, potentially with an add on keyboard with a real 10 key number pad may make her much happier than a 17" laptop on its own.