Tokyo in May (spending a couple days)

Hi!
I'm going back to Asia for the first time in 4 years and my plane ticket for my destination has a stop over in Tokyo. At first I was going to fly over to Japan just to visit anyways but since this opportunity came up, there was no way I was going to let it go! (I'm probably only going to spend 4-5 days maximum)

I was wondering what you would suggest: should I tour Tokyo myself or go with a group? I don't know any Japanese but I am bilingual in English and Mandarin (which I realize will be completely useless in Japan except for maybe being able to read a couple words in traditional Chinese). I am a female and I'm not sure if anyone is travelling with me yet so I was wondering if bus tours would be good....although I enjoy travelling and and touring places at my own pace. Would it be difficult to navigate and travel Tokyo by myself? Does anyone have any links to bus tours that are offered? Anything would be great, thanks!

When I lived in Asia I've always wanted to go to Japan, but now that I've spent 4 years in Canada I have no clue what to visit and what to do in Tokyo anymore...I saw that May has the Tokyo sumo wrestler tournament (does anyone know where I can possibly purchase tickets for this?) and I'm hoping to do a bit of sakura tree viewing and temple visiting but have no specific locations in mind...would anyone be able to provide me with any tips please? :)

Thanks a ton in advance!

Tokyo
http://www.japan-guide.com/e/e2164.html

Kanto
http://www.japan-guide.com/list/e1103.html

Cherry 2012
http://www.japan-guide.com/e/e2011.html

Sumo
http://www.japan-guide.com/e/e3022.html

Well.. I do think it will be more fun having a company. Plans might go like that.

Day 1 - Have a good meal at Tsukiji Fish Market. Visit Tokyo Tower, thereafter shop at Shinjuku and absorb night scene of Kabukicho in Shinjuku.

Day 2 - Asakusa; including Nakamise Shopping St and Temple. Ueno Park for Sakura (Not very sure if there still will be as I was there in April..), get some dried snacks at Ameyoko Market (Green Tea Kit kat the cheapest over there). Visit Akihabara Electric town if you are keen in anime and toys & collectibles, experience maid cafe. Shop and dine at Ginza thereafter.

Day 3 - Shop/Sight See Meiji Shrine, Harajuku and Shibuya. Recommend to start the day earlier as the Shrine gets really crowded... I would take a train to Hakone, stay a night..

Day 4 - Explore Hakone, enjoy the hot springs and scenery.

Day 5 - Make the trip back to Tokyo..