Nah, you will run out of hard drive space, you need atleast 50gb to be safe. I don't think buying an external Hard drive with it is worth it.
Chromebooks are a rip off and waste of money. If you're shopping for affordable laptops with good performance, look into this one. Highly would recommend. https://www.amazon.com/Acer-E5-575-...id=1490821234&sr=8-1&keywords=laptop+i3+7100u
Most pcs have decent hard drive and cpu to run rf. Have atleast 2gb of ram and a decent internet connection. Lags mostly comes from your internet.
I think he meant stuttering and FPS lag. You'll be fine with the 4GB on small games like RF. I would recommend buying another 4GB stick if you're worrying about that but I don't see a point.