Luis-
USB is yes the simplest way to do it, but if you’re recording 1080 you’ll find it’ll take a long time to dump the footage over USB, and keep in mind you’ll be unable to use your camera while this takes place.
The most efficient way to do P2 (IMO) is to use the biggest cards you can find so you can shoot all day and then transfer everything later, although this is more critical for situations where you can’t easily bring a laptop/hard disk around, i.e. documentary/news.
You can rent the highest-capacity cards for not too much money, but think about getting a couple of 4 or 8gb cards to have on-hand since you’re buying the camera. Serious investments in P2 are probably not worth it until there are affordable 64 or 128gb cards.