WD Mybook live pluged directly into ATV2/3

Hi I want to know if you plug a NAS drive (I am thinking a 2tb my book live) directly into the ATV through the ethernet port if the drive will be located by the ATV. To be clear what I want to do is WD live straight to the ATV NOT the wd into a router then into the ATV. My concern is that there is no way to run a ethernet cable from the router to the ATV and I do not want to try to stream 4gb movies over WIFI (I know people do this but I also know it is the #1 cause of problems).

I am not overly concerned about viewing the drive from other areas of the house as I am doing this for my parents and the drive will be fully loaded when it is connected. I know there are several power line options I could use to deal with the issue of not running a wire but this would add approx $90 to the cost. I am then looking at the cost being ATV $110 + 2tb drive live drive $160 + powerline $90 + firecore $30 for a total of $390 to get the ATV working. Without powerline it will only be $300 which comes in cheaper than a boxee box set up $190 boxee + 2 tb regular drive $130 at $320 to get it running. (ALL PRICES CANADIAN).

I am currently running a boxee box  at my house but actually enjoy the hobby of setting up different systems and my parents (based on no actual knowledge) like the idea of an ATV 3 better than the “funny looking” boxee box.

Any help would be greatly appreciated hopefully my post makes sense but I am certainly no tech guy just enjoy figuring stuff out as I go along.