I bought the Conan Crom! bundle from DriveThruRPG, and can’t wait to get started GMing Conan now that the Fantasy Grounds ruleset is finally out!
Which of the books can I show to the players? Is it only the Quick Start and Player’s Handbook, or are some of the sourcebooks for GM and players as well?
I am fond of keeping all the cards close to my chest. That being said, all of the splat books have talents, gear, and even spells that my players can use. I edit the pdf and give them the modified copy (i.e. just the pages or portions with player resources I allow)… You can use Adobe to do that or even just use the Windows snipping tool to take shots of the relevant portions…
Players don’t really need Horrors of the Hyborian Age or Ancient Ruins & Cursed Cities.
But all other books have interesting archetypes and castes that go well with them. With those books having extra talents, weapons, and gear having more choices is what is best in life.
None of them!! They’ll spill their drinks on them, get crumbs stuck between the pages, grubby pencil lead thumb prints on the pages (at least you can rub them off), sneeze and cough while reading, use them as leaning boards while scribbling info on their character sheets… and that’s just the adult players
NEVER! HOARD THEM LIKE CONAN DESIRES ADVENTURE AND GOLD!!! 
So those books can be shared with others, they don’t include GM-only info, such as adventures or NPCs or monsters?
Yes, they all include those. Mot always monsters, but certainly foes. Best limit it to the chargen stuff - Talents and Archetypes, Stories and Natures - usually a few pages.
Although, the gazeteer stuff is oftenintersting to players if their character is from somewhere int he book. Not enough detail there to spoil much, either.
Yea horrors of the hyborian age have the extra creatures in the books and ancient ruins & cursed cities have layouts of possible cities and dungeons.
You could add jeweled thrones of the earth to that as well because it is a collection of adventures you can run.
Horrors has one of the more interesting archetypes in it though. The Beastmaster probably should have been in Conan the Barbarian, but isn’t. That is the only reason I’ve even shown Horrors to my players though. It’s just one page.
That is true but I had someone play a beastmaster in a one shot and they had two animals and their actions took up the majority of the players team side of combat. So use that archetype with caution.