When I first had Izzie I tried to crate train her, it didn't last and she and Obi have the run of the house. I got a coop cup, which although isn't that big, would hold probably a pint of water. It clips onto the sides of the crate and can't be knocked over.
Have you tried putting his crate in the larger area and leaving him there with the crate door open so he can go in or out? Just a thought.
There is a pets at home where we live so if he does get hot and the water is not enough then thats deffinatly and idea..
In respect to moving his crate, he has enough room in his little area if we leave the crate open the only problem is he dosnt like being left in it he continuously whines and cries at the moment I cant get him to settle but its somethingwe are working on at the moment..