Maybe taking some plants out would be best to fit in the cool side hide. I can fit another hide in my 20 gallon ever since I took out this one plant. The snake really needs that cool hide, so I would say get it in there as soon as possible or whenever you can.
It the one hide I have that is large. But she likes it and wouldn't take it out for the world because if I place it on the bed and hold her... she tends to find her way to it still haha. So I guess I'll have to go towards a 40 gallon to put another one in.