Hey, guys, thanks for these great responses.
Meanwhile, my opening post for this thread was actually about five times longer than what the mods finally approved and posted (I guess I was too long-winded!

) . The stuff they edited out was extensive plot details that would have clarified a lot of things for you all. One plot point in particular was that my main protagonist has to drive a car up the side of the mountain to meet the helicoptor. So ... the hypothetical background story suggested by
Bravo 73:
"No road access hence the helipad," doesn't work for the purposes of the plot. But your suggestions are certainly welcome. I'm helicoptor illiterate, and I need all the help I can get here. (In fact, I've never even been in a helicoptor!

)
And,
Bravo: great shot of a mesa! Thanks!