Re: what clothes would be appropriate for a 1yr old girl on
Take whatever she's comfortable in. If you want to doll her up catch some of the sales on Christmas dresses. I think the easiest thing for dinner would be the one peice outfits with the built in feet (much easier than diving under the table countless times to retrieve her socks).
I would suggest bringing both warm and cool weather jammies-that way she will be comfortable with whatever temp the cabin is. bring a hat to protect her from the sun (i always bring a bottle of water babies sunscreen as well) and a supply of whatever brand of wipes you use (they have very limited infant supplies on board).