Linux-friendly laptop for my grandma

Right now my grandma is using an ancient Dell Inspiron [I-don't-even-remember]-thousand and a very stripped down version of Debian with GNOME Classic and a custom idiot-proofed menu so she can't even get into the settings to break anything. She lives a few hours away so I use TeamViewer to take care of any issues or updates. Unfortunately, the literally-13-year-old-laptop (I gave it to her out of my junk pile because she didn't have a PC, the plan was "get her hooked on the internet, and then she'll front the cash to buy a cheap laptop later when this one quits" and it seems to have worked perfectly.)

I need to start looking at a new laptop for her so I can point her in the right direction when this one finally does give up. I need a 15 inch or bigger screen (10in is too small, she won't be able to see it well, but 17 is a bit big because she does carry it around the house occasionally)

I would like something with an AMD A4 or comparable (like the APUs because their graphics aren't awful like Intel), at least 2GB of RAM (4 would be great but I have a couple 2GB sticks of DDR3 I can put in there if it only comes with 2), 802.11n wifi, a decent looking screen (she's using 800x600 right now so her standards are very low, basically anything that isn't raw film), and either a small SSD or a 500+ gigabyte HDD. It also needs to not be a giant power hungry beast, she would like it to be sort of portable so she can carry it around the house, sit outside without the battery dying in 15 minutes, just general stuff like that. I basically need the HP Stream but with an APU if that's an option.

Any suggestions? Again, her standards are pretty low, the Core 2 Duo would be 1000x nicer than her current processor (a 2GHz Celeron single core) so I really just need something that'll be easy to put Linux on and won't just absolutely make her wanna pull her hair out because it sucks so bad. And preferably for less than $250, but if there's higher priced options that are reasonable I'll at least look at them.

Find something half decent 2nd hand for $150 then buy & install a ssd. So check out ebay or your local classifieds.
I'd dare say you'd be able to pick up maybe a first gen i3/5 model. Nothing wrong with any moder'ish intel igpu chipset btw.

BUMP

Hey guys, I found this laptop at Best Buy and it looks like it'll do the trick. I might swap out the HDD for a tiny SSD just for extra speed, but I dunno.

http://www.bestbuy.com/site/hp-15-6-laptop-amd-a8-series-4gb-memory-750gb-hard-drive-black/4445025.p?id=1219629073145&skuId=4445025

Does that sound reasonable?

Also one BIG thing: Secure Boot. I don't THINK this thing has it, but if anyone knows a lot about that and can shed some light on whether or not it's gonna be impossible to install Linux on this, that would be fantastic.