We're going to Amsterdam at the start of July, and want to go to Eurodisney for a couple of days, so travelling from Amsterdam to Marne-la-Vallée on Monday 7th July. 2 adults, 2 kids (8&10).
We wouldn't mind stopping off in Brussels for a couple of hours to break the journey.
It seems that we can go Amsterdam to Brussels on Eurostar and then on to Paris on inOui.
I'm a bit confused by the train booking, though. Some are saying "Not available" - I'm not clear whether that means "No seats left" or "Booking hasn't opened yet". There also seem to be quite a few different booking sites - any recommendations for the best one, or even advice on the differences between them?
Also pricing - are there any travel cards or anything we can get to make things cheaper, or is it not worth it for a one-off journey?
Any tips from someone who's used to this kind of travel?