I went in september, JUST missed Comiket lol... it was wayy cheaper to go in september, still got to go to TGS so it was all good... In Tokyo I think Ikebukuro is very good place to go esp if there's any fangirls in your group as it has the most anime stuff for girls, rather than Akihabara.... and the best Animate is in Ikebukuro imo and theres a few cosplay shops and stuff there (I stayed in a hotel in Ikebukuro for nearly 2 weeks and only discovered all this in my last week there me and my husband were gutted lol..well he mainly blamed me as I can speak japanese and stuff and didn't find it sooner.... XD) The anime/manga/doujin area is a bit hard to find, its past sunshine tower (or maybe its at the foot of the tower) you have to cross this big bypass thingy to get to it but it's worth it I found stuff in that animate I didn't find anywhere else (and we spent alot of time looking at anime/manga stuff...) It's starnge not many people mention Ikebukuro idk why as it's really good for anime shopping there Akiba is a bit overrated...
And theres Sunshine city which is quite a cool place to go (Very very tall shopping/entertainment complex in Ikebukuro has really fun stuff to do there) and lots of arcades to amuse yourselves with
And cosplaying in TGS was great fun
I also went to Universal Studios Osaka and Tokyo Disneyland among other places but that's really up to the person I wanted to take husband there he had never been even as a kid lol
Hope you have fun there
And if people like models/figures its best imo to go to Denden Town in Osaka it had much better choice then Akiba did according to husband I would have no idea I'm not too intrested in models myself lol