Running route close to Roppongi

Hi everyone!

I am traveling to Japan this March and usually (unfortunately) leave my running schedule back home. Now, the reason for this is not laziness, rather, I have difficulties finding good routes in Tokyo to run along.

Apologies for being very detailed here but I am looking for a route, preferably walking distance from Roppongi where I live, where I can run freely without having to cross roads, stop at traffic signs or run next to cars in small alleys. Above this, I would like a route where I can push 10 km at a 4:00 pace each kilometer without bothering others.

I heard about Yoyogi and such but something tells me it might a bit "rude" to run quickly at those roads where people sometimes walk slowly and just want to relax. Maybe not having to move aside or worry about a gaijin puffing with a blood red face pushing forward.

Any ideas or suggestions will be highly appreciated by me and my future health.

Thank you!

Vinc