Alright, I don't know how much you guys have played with the castle blocks but I've realized that it takes a lot of blocks to make even a small extra building. Yes, the Midday Estate, Meadows at dusk and the Night Garden are bewitched to allow an extra 250 castle blocks inside and out but the castles pre-built already take that many or more! You can get elixirs to increase the amount of items you can set down but that only increases the amount total, not the bewitched castle blocks allowance. So if you don't want to spend a ton on elixirs the only solution I can think of is to use as many of the XL pieces as you can and try to avoid the small and XS where you can. My buddy Lloyd Fallingwater, you know, in the Shopping District, he pointed out some huge pieces that can really help you free up some space.