Making a crossover cable is cake, though if you want to add some network capacity (i.e. more ports for future connections, because once you go to more than two PCs, it never stops lol) then get a router/switch and do it that way, but the crossover is definitely more cost friendly.
I use this page to help me wire up crossover (cross connect) cables and every other edition of cables:
You can also find tons of tutorials on YouTube if you search "how to make crossover cable" or "how to make ethernet cable"
Once you have the systems wired up together, get yourself a copy of SyncBack (Free!) and it can set up automated backups for you. Just make sure the system is on and you can tell it to copy to another internal drive, or a drive in another computer.
FWIW, hard drive failure rates are purely observational. I have drives from WD, Seagate, Hitachi and Samsung at my house and they all work flawlessly - and I HAVE had bad apples from every one of those companies save for Samsung (it's my first drive).