I am buying a corn snake but i am trying to figure out the best things o include in the teranium(size too)?

for now that size aquarium is appropriate, but invest in bigger ones as she grows. she may be 3 to 5 feet long, so eventually 10gallon tank should be the MINIMUM as she is growing, ultimately at her big size she should live in a 20 gallon one. ok let me think...water dish...aspen chips...rock hiding place...some plants...hiding place or branch...moss....yeah i think you got it covered. she'll be really happy :3