Tokyo Station is not the primary hub for in town travel. Otemachi is a large subway hub, which is a few hundred meters from Tokyo station, but you have to understand the layout because you can have another few hundred meters walk inside Otemachi depending on the entrance vs. line you are taking.

If you want to go to Roppongi frequently (and not stay there) then the Hibiya line will get you there. Upscale hotels near Hibiya Station include the Peninsula and the Imperial. The Hibiya line continues into Ginza.

Shibuya is a good transport and entertainment hub and there are two upscale hotels (Tokyu Excel and Cerulean). To get to Roppongi from Shibuya you can easily take a bus or taxi. Taking a bus might be a concern but it's pretty easy. It's the green and yellow Toei Bus #1 from the east side of the station. Very frequent and there is also a special bus marked RH1 that takes you directly to Roppongi Hills.

I don't stay in hotels in Tokyo so can't recommend any.