eh i neber wear kimono walk around before, but i think popular spots would be in Asakusa itself (the Sensoji temple). Nearby Sumida river (5 min walk) is a hanami spot, so maybe you can try there also. dunno if you want to take river cruise but i think will be crowded and long queue.
From Asakusa the easiest way is to take Ginza metro to Ueno Park - hanami and got temple there also. Then from there can take Yamanote line to Shinjuku gyoen. I saw ppl wear kimono take photo with sakura trees there. also got ppl take wedding photos. so it's a popular spot for photo-taking.
I would skip chidorigafuchi cos really no time, unless you can go evening/night (i think it has night sakura lightup event or something - not very sure). You can easily spend 2 hours in Asakusa, 2 hours in Ueno and 1-2 hours in Shinjuku gyoen. I walked from Tokyo station to Imperial Gardens to Chidorigafuchi (cos supposedly got sights along the route) and it was a very, very long walk. there's a nearer metro station if you dun wan to walk, but overall i wasn't very impressed with chidorigafuchi (maybe cos i went too early and for some reason sakura haven't bloomed there yet).
