Ken, Sure, extend the invitation; you don't get anything in this world if you don't ask for it. The worst that can happen is that he would say "no". (I'm sure some wise guys reading this are thinking, "The worst is that he might say "yes".")
Frankly, I would be astounded if he had the time to pull up a chair to the Campfire but you never know. He would be a tremendous asset to the forums and help fill the void left by the departure of Muledeer(that sure was good while it lasted, wasn't it?!). As for how he would be treated, who knows? He might get flamed off the forums the first day or might be granted the respect that a man of his experience and knowledge deserves.
I met Craig, briefly, at SCI in Reno some years ago. His time was, as usual I suppose, in short supply but he asked how the convention was going for me, had I booked any hunts, etc.. He answered some questions I had about a couple of outfitters and then politely begged his leave for a meeting. Whether it is true or not, he left me with the impression that, had his time not been spoken for, he would have talked with me all day.
Through the years, I have read much of Craig's work and while there have been many instances where his thoughts on various subjects were at odds with mine, I have usually found him interesting. There is no doubt in my mind that if he wrote for, say, Wolfe instead of Peterson(or whoever owns them this week), he would be even more highly regarded than he is now. I think that his books demonstrate this notion.
In the end, extend the invitation. Great idea. RS