Just as a quick followup, I was out at Pipit Hill last Wednesday, and the access is exactly as described by David and the CPW tech I spoke with beforehand. You can drive out the usual spots, but I'd advise crossing the fence at the top of the hill where the gate is, just because it's easier. The gate seems to be kept shut but is not locked – just unwind the chain, proceed through the gate, and put the chain back as you had found it. Access to the rest of the area is unchanged from before. (If by chance you find that the gate is open, then just walk on through and leave it like that as well. But please do not open a shut gate and leave it open.)
For the record, that day while there I had a flyover that sounded very much like a Sprague's, but I could not confirm that's what it was, and it landed pretty far away from where I was.
Good luck!
Eric
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Eric DeFonso
near Lyons, Boulder County, CO