We have an '06 Allure with the Cummins ISL 400 but hopefully some of the same things will apply:
#4: we have a hydrohot and the whole house filter is located in that bay.
#6: most likely in the bay where the power cord is or in the bay directly below the breaker box
#8: unless real cold we turn the thermostat down and put it on electric only and close the door in the bedroom...helps a lot; also if you have electric floor heat like we do then turning that up to a high setting will allow you to reduce the temp on the furnance as it will make the floors nice and warm when you get up and then turn on the diesel for a quick room warm-up. otherwise all i can say is that it is still lots quieter than our last rig with a propane furance.
#9: on our rig it works in conjunction with the cruise control; what we do is set the cruise to about 5 MPH below the posted limit and generally speaking let it work automatically; seeing as you're in Southern CA I will relate that we regularly go down the Cajon Pass ssetting the cruise to just over 50 at the top and never having to touch the brakes (unless we encounter a slower vehicle in front of us) and will never have the rig get beyond 65; if you have a true jacobs compression brake there will be at least 3 settings -- high, low & off; since we drive a lot in the mountains we usually leave ours on high for maximum braking
#10: unless changed recently and yet "burped" you shouldn't have to add much coolant on a regular basis...if you are adding a lot regularly you may have a leak which coudl be as simple as the clamps requiring retightening.
You should check out the yahoo CC owner's group as that is very active and can probably get you even more info (http://autos.groups.yahoo.com/group/...wners/messages