tokyo is easy to diy. yup i agree that not speaking japanese is not a big prob, as long as u can read chinese. furthermore tokyo is so cosmopolitic that chances are, when u really nd help, u will come across someone who speaks either mandarin or english. and i suggest getting out of tokyo (easily done by train) to nikko/kamakura if u like temples/shrines, or hakone for onsen and nature sights.
for hakone, i will suggest
http://www.odakyu.jp/english/freepass/hakone_01.html
it covers almost everything in hakone, includes round trip train ride from tokyo, buses around the area, theres also ropeway (cablecar) and cruise (may b able to catch sight of mt fuji if sky is clear). all at a very reasonable price of 5000yen~ish. can get e tix from any tour agencies there (they charge minimal or no service fee), which can be found at/near all major train stations.
personally hakone is my fav place out of nikko, yokohama, and kamakura.
if u r too lazy or have no time to do side trips, theres lots of interesting places to shop or walk around, odaiba, shibuya, shinjuku, asakusa, ikebukuro, akihabara, kichijouji, rippongi etc etc. all these places have their own character, depending on what u want to c.
and hokkaido has to be my favourite place in japan. just the food itself is enough to compel me to go back. seafood (mostly raw) and ice cream (soft serve) especially. its also one of e more rare places in japan where u can find lamb/mutton.
will be happy to share if anyone needs more info =)