We took our kids about 8 years ago, March time, it was quite reasonable and not too busy. We travelled by Eurostar which takes you straight on to the Disneyland complex, the staff take your cases to the hotel so you can go straight into the park, we live just outside London so getting to Waterloo was easy for us. I was surprised at the prices, I thought they'd be extortionate when in fact they were very similar to any large city. We had a great time, well the kids did and that's all that matters.