Dick - Our Marquis is "a real power hog" too, as you put it. Many times the generator auto start will activate before we can get set-up when boondocking.... and this is immediately after a couple hour drive, so all the batteries are charged up when we park. The six-pack of golf cart batteries supply a lot of power, but it seems not enough to run the coach for very long... maybe 45 minutes.
We don't know where all the power is going. Over the last couple years we have adjusted to it by unplugging the insta-hot and tried to keep other plug-ins at a minimum... like the computers and phone chargers.
What we have finally done to adapt is to defeat the problem as cheaply and effectively as we can. We purchased a 3,000 watt, 75' remote start, 4.6 gallon fuel tank capacity generator which is kept in the back of the toad. The Marquis's power cord reaches the generator easily with the toad hooked up in tow. We can park, hook up and start the remote generator, extract the slides, level the coach, etc. and leave the generator running. Obviously, when we boondock we park such that the running generator sitting on the tailgate of the Avalanche will not bother other campers. This generator soon settles down to generate only 20% of its capacity - enough to have power for two TVs and the fridge on 110v. The 4.6 gallon gasoline tank will run for 20 hours or more if I leave it on. It's cheaper than paying to stay in a $30 per night RV park. The downside is every couple days we need to fill our gas cans.