I'm landing in NRT on Monday and leaving on Friday. I come in on AA Terminal 1 and leave on Friday through JAL in terminal 2.

Since I have three weeks worth of luggage for my final destination, and only need 3 days worth in Tokyo, I was going to leave my luggage in the left luggage area. Should I leave it in Terminal 1 (where I arrive) or Terminal 2 to make it easier on my return?

I thought about landing / immigration / customs and then taking the shuttle to terminal 1, but I'm not sure if you can board the shuttle after going through all of that or whether you can only transit from "within" the secure areas. Are there shuttles after you get through everything, or are they only for same day transfers?