make sure you stay inside the Disney complex, catching a coach/bus/train from outside takes time and when the kids are tired the return journey will be hell.
Santa Fe is the cheapest and there is nothing wrong with it, its clean, bathroom fine and the breakfast is okay. free bus takes you to the entrance. Cheyenne is the next cheapest but remember you will be out all day, its just to sleep in.
Travel tip, take your own travel kettle[ from Argos] tea bags and powdererd milk, & 2 cups, they dont supply a tea & coffee maker to the rooms and theres nothing like a cuppa when you wake up.Evening meal in your hotel [ buffet style is cheaper than eating outside] you can take the free bus to look at the other hotels inside the complex and eat at their buffet on your second & third night so you get a variety of meals & choices
I have been by coach [ time wasted at Dover waiting for coach to board Eurostar train is about 2 hrs] and I would not recommend, but Eurostar from Waterloo was brilliant and so fast, I did two crosswords and we were there, the train doesnt stop and it takes you right into the complex where a free bus drops you at your hotel, real hassle free journey and even the buffet car serves decent snacks and not too pricey either.
Buffalo Bill's Wild West Show is great for kids and though not cheap you do get a big meal during the show.
Take macs, the weather can be a real downer.
Also on arrival in the park, take the Disney train that goes right around the whole park, that way you can decide where you want to go to first and it gives you some orentation.