That's what I was trying to avoid and what I ment by spin but I gets it's the same game on both sides of the isle. It's either "Go read Genesis" or "Go back to College".
It's just that the questions you're asking aren't simple ones. They're at the core of astronomy, and astronomers have devoted much time and work to their answers, and the answers aren't simple. It's going to be very hard indeed to answer a general question like "how do we know what we know?" to a non-scientist on an internet board.
You'd do much better to read something like Hawking's "A Brief History of Time". He explains it all so much better than any of us here could do for you, and it's very much a book for intelligent laypeople.