Sure. Beginning of April is the best, and go for at least a week. You could easily spend the whole time in Tokyo but I'd buy a rail pass and go to other cities too.
For Tokyo, do the sightseeing first ex. Sensoji temple, imperial palace, Tokyo tower instead of sky tree since that's too crowded. Then shop in Shinjuku /Shibuya, etc. Keep one day just for akihabara/ikebukuro if you plan to do any sort of anime or tech shopping. Make sure to take a night bus tour especially one that passes by the rainbow bridge.
As for other cities I went, Kyoto is interesting only if you like to see 1000s of shrines but not much else there . Don't bother going to osaka, it is a nice ultra modern city but you're on your own since there arent many facilities for tourists. I haven't been, but I would love to go places like Sapporo, Nagoya and Kobe.
Japan used to be super expensive but not as much now because of the falling currency value. But it still costs a fortune to rent a hotel room not much bigger than a closet.
Honestly Japan is one of the best places I've ever been. So if you ever go, make sure to have fun, eat yummy food and shop like crazy. I would love to go again.