We have no seperate heat to toilet room either, but leaving the door open (while parked) I think is the idea behind the design. The gap at the door bottom is enough to keep ours acceptable except in the coldest of weather anyway. We noticed the cool toilet room when the coach was purchased new (October '06), but just learned to leave the door open in very cold weather while parked - no big deal unless you park your rear in the throne room for extended periods in the winter.
You should consider installing a secondary pump switch in your utilities bay, like our '06 Monterey and others have. I'm very surprised an '04 Patriot doesn't have one. The other solution is to not fret so much about possible leaks, and leave the pump on most of the time.
Joel