Graham....my Newell has a propane water heater. It only works on propane. It is located beneath the passenger side hanging closet in the rear bedroom. There is an access panel in the closet.
What kind of generator do you have (diesel, propane, gas), and what make? The generator should have its own radiator and cooling system (I have a Kohler LPG 7.5kw). The chances are the coolant lines you see running to the front of the coach are for the chassis heater, if there is one up front, and I believe that you will find piping in between the rear and front.
As you can see, help is ready and willing here. It might be better to start new posts on specific topics under the chassis, electrical, etc headings than to continue on this thread.
That way, more people, and therefore more help, is likely to pick up on the subject. Also, it will make it easier for others to find the answer to a similar issue in the future.
I don't mean to sound like the Grinch, just trying to maximize the benefit of the forum.
One more thing that will help is to use a digital camera and post pictures of the latest "thing" you are trying to identify.
It's a steep but short learning curve you are on. Hang in there, and you'll be one of the go to guys soon enough.
Richard Rhonda Ty and Alex Entrekin
1995 Newell # 390 DD Series 60, Allison World Trans
Subaru Outback toad
Often wrong, but seldom in doubt
Rhonda's chronicle https://wersquared.wordpress.com/