There’s a few great places to see the cherry blossums
I personally liked in Tokyo:
-Chidorigafuchi either early morning or late late evening [they have rowboat you can rent but you’d have to go line up before opening time]
-Meguro river very early in the morning (less crowds)
-Shinjuku park (paid entry so ~less people)
-Ueno park (you can also line up to rent a swan paddle boat)
Accomodation wise, just anywhere close to a subway station is fine, you can buy a subway pass (1 or 2d) and go sakura-hopping.
Kyoto I’m not as familiar, but I liked philosopher’s path