Your looking at the Dream? I honestly can't tell you about the 3 or 4 day trips and pricing because we only do 7 day cruises. I know we looked at doing a 3/4 day b2b but they always came out to be more expensive than the 7 day on the Fantasy.
How many people are you sailing with? It's just me and DH, and our Very Merry Cruise that left the Saturday after thanksgiving last year was appx $3,530 for a verandah. We used our on board booking credit to book it, and we are right about at your $250. I should also say that I booked it on opening day so we got in a the lowest fair.
Keep watching, you may luck out. You may also want to check out some of the threads that talk about buying gift cards at discounts to reduce your cost, as well as credit cards with cash back or the Disney Visa for free 6 month financing to lessen the "pain". Some travel agents also give you on board credit.
Hope you find the cruise you want.