Isn't a patch cable the same as an ethernet Cable, if not then I stand corrected, just a normal Ethernet Cable will do.
But, as said before, if she has the retina she can't and needs an extra TB/Ethernet Adapter or a TB/FW adapter which is more expensive than buying a USB casing/enclosure and put the HD in there.
Edit: I work with electronics and we always called them Patch Cables.
Well there is actually a difference. A 'straight through' ethernet cable has each wire corresponding with a 'pin', which is the same 'pin' on the other side.
So, in the example of ethernet;
1 -> 1
2 -> 2
3 -> 3
4 -> 4
5 -> 5
6 -> 6
7 -> 7
8 -> 8
That's a 'straight through' ethernet cable. I HAVE heard people call it a 'straight through patch' though. But, I guess I've always referred to 'patch' as a crossover cable, in which;
1 -> 3
2 -> 6
...and so on and so forth. It's sort of convoluted. To connect an ethernet client to a router or switch or modem, you want a straight through cable. To connect to ethernet clients together without the aid of a router or switch, usually, you need a 'crossover' patch cable. However with the MacBook, the computer automatically does the 'crossover' functions in the ethernet port, allowing any ethernet cable to work as a 'crossover' cable for linking two devices together without a hub or router.
I may be the one who is mis-labeling them though. I guess I've just always heard 'ethernet' or 'straight ethernet' vs. 'patch' or 'crossover patch'. You rarely hear about them anymore. Nowadays, people have several computer in their home, home networking equipment is dirt cheap, and everyone is wireless anyway...
Speaking of which, you CAN use migration assistant over Wi-Fi as well, but it'll be very slow, even best-case scenario perfect signal dual band 5GHz wireless N, is less than half as fast as ethernet.
The first home network I ever did was with a 50 foot crossover cable, I had a PC in the basement, and a Mac upstairs with an external dial up modem. It was really really tricky, but I managed to share the internet connection between the two machines, along with some files, using a crossover cable. I even got it working well enough that if the connection was dropped, the Windows client could force the mac to reconnect (back then I had two phone lines; one for always-on dial up. Today I have NO phone lines and always on cable! LOL). Networking Macs and PC's is a cakewalk now, in fact I find networking my Mac to my Windows PC's easier than networking two Windows PC's, but back then it was a nightmare. That was Mac OS 8 and Windows 98 IIRC.