I think that you will be able to best keep it in a large plastic "stock tank", like a water trough that you would buy for cattle. They prefer to hide anyhow. And the round shape will be good for them. They have extremely long whiskers and I've been told that they should be kept in an area big enough that their whiskers aren't forced to touch both walls of the tank simultaneously all the time. Apparently it stresses them out... I would say a stock tank of 4'x3' if you can find something like that.