Hey there Simon and welcome to planDisney!
28 DAYS AT THE WALT DISNEY WORLD RESORT?! You are literally living my dream. But despite my being Maleficent green with envy, I've still got an answer for you! So you could essentially book a
Disney Resorts Collection hotel for up to 30 nights. The problem you may run into is availability at a single hotel for that long. Everyone wants a piece of the Disney action! Let me suggest to you a tried and true favorite tactic of mine that is sure to be a next-level adventure. A split stay! You could make bookings for several hotels on property and switch at certain intervals in your trip. For example, you could spend the first half of your trip gazing on the savannah at
Disney's Animal Kingdom Lodge. Then at the halfway point, pack up, take your bags down to Bell Services and have them move your luggage to your next destination. Perhaps
Disney's Beach Club Resort to give you that touch of seaside splendor. I did the math on your stay and you could actually stay in 3 different hotels and only have to move once a week before it's time to go home!
Simon, I don't have to wish you a great trip. 28 days at Walt Disney World can't possibly be anything else.
Happy planning!
Taylor