Bruce,
If the hose freezes the frost free hydrant is no longer frost free. It too will freeze. I would insulate the hose!
If you insulated the outlet drain with 2 inches of insul. making sure it is air tight esp. next to the tank, I don't think you would need any heat to prevent freezing of the outlet. The water in the tank will prevent freezing.
BTW I too envy Cecil & his huge trout & perch!
