Paul ... my wife and I are spending more than 6 weeks in Colorado, mostly at three mountain-top, no-service campgrounds from late May to mid-July this year ... we can get three days (or longer) out of a Jump-It emergency battery ... and can leave most 10 day dry camps with a fully-charged house battery. (We space out 10 or 12 day dry camps with a couple days of commericial electric/water to recharge/do laundry/get groceries, etc.)
In fact, we try to save most of our Jump-It battery power for an occasional furnace
cycle (first thing in the morning, getting ready for bed at night), to take the edge off the trailer.
Takes a lot of practice ... but briefly, here's how we do it.
1. Flush toilet with a gallon jug of water, instead of running pump to pull water from fresh water tank. No need to use the whole gallon of water ... in fact, flushing with a jug gives you more control over how fast your black tank fills up.
2. Use solar
candle, various stand-alone L.E.D. and fluorescent lights
inside the trailer at night, instead of running the trailer's house lights.
3. Do most of your cooking and dish washing outside the trailer, using water heated over a campfire or propane
stove, instead of running stove exhaust vent and water pump, pulling hot water into sink. I even dart out in the morning to fire up some hot water over a fire or campstove for morning coffee and tea.
4. Use a solar/crank am/fm radio/flashlight for tunes and news instead of running tv or radio off trailer battery ... although we love to be in spots were you can't receive tv/radio/cell or even national weather service broadcasts. If you get good reception, you're camping too close to civilization!
5. Use a Coleman Black Cat to take edge off trailer, during a daytime cold snap or shower (spacing out in-trailer showers with dips in nearby hot springs or bucket "military-style" showers).
Now, rain and even an occasional summer mountain-top snow-storms can alter the best-laid plan, and cause you to use more power (which is why I carry a number of Jump-It's).
But if you think ahead, and think of ways to NOT use the power of your trailer battery, you'll be able to extend your dry camping
I know, I know, some of you are saying, "wait a minute ... why should I have to act like I'm camping in a tent when I'm in a fancy trailer."
Well, if you are going to spend six weeks in the mountains, dry camping
, far away from society ... which by the way, is just an absolutely wonderful way to get one-on-one close with your spouse ... you need to alter your thinking a bit.