I'm restarting this thread with the addition of Part II in the Subject. My comments relevant to Part II are below. I added them to the the old thread, but they have gone unnoticed. If there any comments about the 600W Xantera or other choices, I'd like to hear about them; otherwise, I'll be purchasing it very soon.
--------------------New Comments at the Bottom of Old Thread-------------- Hi, I left for my 3 week vacation on the 9th, my last post. I was unable to really start installing it, so figured I'd do it on my trip. Fortunately, I found a much better solution on my way before I tinkered with anything. It's called a power pack.
When I happened into the Tower campground in Yellowstone, I asked the campground host if he had any electric outlets I could borrow. One thing led to another, and he offered me the use of his Xantera 600W PP. It worked fine in that it powered my CPAP unit for 8 hours. One can recharge it by plugging it into the car's 12v outlet.
Although I don't need it, it has a radio. alarm, and a light. Allows for 3 AC devices. I used it for 3 nights. I think Xantrex makes an ever higher wattage one. Amazon has it for a lower price, much lower depending upon how shipping figures into it. The campground host told me there might be a bigger (wattage) model.