ProCycle,
This is why I am a big proponent of using a shunt based battery meter/monitor. One not only will have an accurate way to know exactly what state of charge their battery bank is, but they also can use that same meter to hunt down parasitic drains. They can also learn how much power each appliance uses. Often times, many freakout about the high current appliances, like the microwave or hair dryer, but those items usually run for a very short duration, and don't make a big dent in the amp/hrs used. It is the little and some not so little, constant parasitic drains that really add up over time, that get you.
I'm curious to know, when you measured the 4.12amp drain, was your microwave unplugged???
The reason I'm asking is, my micro wave draws at least 4amps with it just being plugged in and not in use. Things like the TV, VCR/DVD player, etc. add up too. I use power strips on all the mentioned items, this way I can turn the power strip on and off as needed. For most people, I would think that you really don't need to run the inverter at night, unless you have a residential refrigerator. I know of one Safari couple that installed a bathroom fan type of timer that they set when they go to bed and watch a bit of tv. After about an hour or what ever the set the time for, the timer shuts the inverter off, and by that time, they are fast asleep. A very nifty solution indeed.
For the ones that need the CPAP machine, most of them can be converted to run directly on 12v, via an adapter. Running those machines on 12v takes much less power and also negates needing to run the inverter.
Do you have solar installed, or do you plan on installing solar on your coach?