Re 12 V coffeemaker....somewhere in these postings, I think someone said their 12 V coffeemaker took so long to heat up that it wasn't worth it.
We heat water on the stove and use a manual drip coffee maker, even when we have 120V available. The water heats in about 5 minutes (never really timed it). We can only put about 1/3 of the water into the coffee pot at one time and wait for it to filter down through the grounds. That takes another five minutes. In about 10 minutes we have some really good coffee.
Opinions are cheap so here is another cheap opinion. Try to stay away from inverters. As pointed out previously they really suck up a lot of battery capacity. If you absolutely have to run stuff off 120 V I'd suggest a generator.

Dick_B