4 month-ish, as he's not born just yet...
We're going to a wedding on the other side of Europe when the baby will be about 4 months or so, and I really prefer trains to planes, if at all possible. It will involve the Eurostar, a connecting short high speed train, and an overnight sleeper train. All the changes are in the same station, so no schlepping about across town to make connecting trains.
I wouldn't think twice about it normally, but I've not had a baby before, so I'm having a little worry about it being a bit mad. Trains seem more baby friendly than planes, to me, but it is a long way... Is it mad??