I have really good experience against Peach. From what I see from ILMATIC (namesearchpleasegurl) if you're playing on somewhere like FD where there aren't platforms, all they do is float, space, and dair if you get underneath them. You have to basically run in and fullhop a nair, fastfall, and run away. If they airdodge, then do NOT fastfall or dair or whatever. They can utilt, uair, what ever. They own when you're in the air. If they pull a turnip semi-close, run in with shield to pressure and/or grab. MOST of my grabs I get are when they pull turnips at the wrong time.
Smashville is very different. Same with the dair, but they can jump on the moving platform and spam turnips. Do not try to jump offstage and upair them. They can bair you by running closer to the stage and dropping down the platform.
As for bans, either Japes or Brinstar. Illmatic loves both, and I've been banning Brinstar but he times me out on Japes. I'm beginning to think that I should ban Japes because Brinsar isn't so spread out. Also if you're CPed to RC, ALWAYS stay below her in the second area. On the boat, force her to the rift side and keep keep SH uair'ing. On the third part, it's basically like a funky BF.
For CPs, do what you feel comfortable on. I'm not quite what I like yet. I like BF, FD, and YI (Especially because they can't do float tricks on the ground OR platform because it's uneven most of the time).
For general tricks, remember Peach can fair onto the ledge, gimp and keep Nana separated easily. If she tries to sideB (Peach bomber) to the ledge too high, dtilt which can gimp her well if she doesn't have a float.
This should go very close to timer. Don't worry. I'd you get a lead, just don't approach too riskily or else she will approach and you might get nervous due to pressure and mess up.
Illmatic, please comment!