Try not eating at expensive resturants, as well... the smaller ones tend to be better from my experience; and in general just have more heart in it (unless it looks like complete shit, then don't try it).
Travel in Japan, especially in Tokyo is easy, JR Yamanote Line literally takes you to all the major stops in Tokyo including Shibuya, Harajuku, Shinjuku, Akihabara, Tokyo, Ikebukero, Ueno and more! However, as you said you only have a couple days.
You must try out Mutekiya in Ikebukero or Ichiran in Shibuya/Shinjuku. Both are amazing ramen places.
If you ever get the time (LOL), try going to Kusatsu. Easily the best onsen place in the world. It's the most famous in Japan by far. It may not be too good during October, but during winter it's amazing. Still, onsens are wonderfully refreshing.
Not too sure what else I write, I've been in Japan for a few years now (only 19 years old), as I live between Australia and Japan. So if you speak English and not much Japanese, it's fine in most places try and hire workers that speak somewhat English.