Hey y'all - have any of you seen a "girly" white top lately that would work under railroad-style overalls?

LO is wearing a train conductor-y outfit for her birthday (Thomas theme): overalls, conductor hat, bandanna, red Converse. I want to "girl it up" a bit, but I want to keep the top solid white to go with the theme.

Basically what I have in mind is ruffly or lacy short sleeves... but this is challenging in the fall! I would also really prefer to buy it in store so I don't have to pay a ton in shipping to get it here by her party on Saturday.