There seems to be quite a lot of walking in that plan - it might be worth knowing about this tourist bus:
http://www.kotsu.metro.tokyo.jp/bus/...ish/index.html

There's also an ordinary bus from Asakusa that passes by Ryogoku stadium - S1 from stop 3 at the corner of Kaminarimon Dori and Kokusai Dori:
http://www.kotsu.metro.tokyo.jp/bus/noriba/asakusa.html

Riding the bus requires a leap of faith ... but hey ... What could possibly go wrong?