I would like to buy a laptop that is primarily for travel. I would primarily use it for

downloading images off cards (USB3 hopefully)
internet/email
Viewing images
some quick Lightroom review/minor edits
light use of MS Word, Excel, Powerpoint

Trying to keep it under $500 but if not possible can increase budget.

I'm wondering how much Ram I would need for this with Win8 and light use of Lightroom?

Also, what's a good compromise on screen size for compact travel and viewing images?

Thanks
Doug