Really depends on it's growth but a baby corn will do fine in a 10 gallon for quite some time. We don't have a corn but we do have another colubrid, an albino Nelson's milksnake. Emi the milk enjoys a bit of climbing but not really all that much but it's fine to offer that option and see if the snake likes it. You can also put in some decorative plastic vines (just check them for any wires sticking through). Personally I like having our milksnake on a fairly deep layer of aspen. She really seems to enjoy tunnelling and my friends with corns tell me there corns often seem to do that too, especially as young snakes. Once a week feeding is fine and I agree that one snake per enclosure is always the way to go.