Also note that when you buy a US Magic Your Way ticket (with a UK dealer or with Disney US direct) you can upgrade your tickets as long as you have one day remaining on your tickets. I thought I'd mention since you don't seem to be set on the number of days you need. you can buy a 3 days ticket from undercovertourist for example, and shoud you need a 4th day, you need to go to a ticket booth on day 1 or 2 and ask to add a 4th day. You'll only pay the difference between the price of a 3 days and a 4 days ticket you can also add hopper (change park during the day) if you don't purchase it as an option. There is a very comprehensive thread about tickets and upgrading on the US part of these boards (theme park strategies) the thread is stickied.