Most of the rides are inside and most queues are covered, not much of a big deal really if you take a waterproof coat + chances are it will be really quiet because not many locals will be there.
I got the train from Brighton to Ashford international, then the Eurostar straight to the train station in Disneyland, it was nice and easy + stress free, however I think you may of left it to late to buy tickets or they will be sky high.
Also don't know if anything else is in this thread that...