A colleague just asked me: Is it "the great outdoors are" or "the great outdoors is"? And I'm none too happy with what then transpired.
Webster's New World and American Heritage online give no instruction on whether the noun takes a singular or plural verb. Dictionary.com and Merriam Webster online do. They both say it takes the singular verb: "The outdoors is a wonderful getaway location."
But I'm not sure I trust them. I'm disappointed that American Heritage online didn't have any further instruction because that's the dictionary that's usually best for this kind of thing. For many such gray areas, the American Heritage includes rulings of a Usage Panel -- experts who give their two cents.
For a moment, I tried to make this a Wonderings and Googlings topic. I tried Googling "the outdoors is"/"the outdoors are," "the great outdoors is"/"the great outdoors are." But it turned up too many wild cards -- stuff like "One person who enjoys the outdoors is" and "Some things you'll find in the outdoors are." Pretty useless.
I'll check my "Garner's" and "Fowler's" when I get home from the freelance gig tonight. Until then ... Oy. Just oy.