Since Ghastly Demise only costs one mana, it's rather easy to cast
I'd start out with one or two tutors that can get your wincons, but if you start working your way up the power scale, having more will be necessary for keeping up with your pod
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Although none of these 150 cards are all that difficult to come by on their own, collecting all of them together can be incredibly difficult
Your opponent will be on the back step trying to find a way to answer the vehicle, and during that time you can keep dropping more and more creatures on the board
White has a handful of decent ramping options as well, such as Kor Cartographer, Boreas Charger, and Knight of the White Orchid - each of which will help find you more Plains in a pinch