...and Gandalf the Grey spent 3 weeks drinking and smoking and setting off fireworks with the Hobbits, remembering his old friend Bilbo who died some years earlier after an average hobbit lifespan with his nephew Frodo...
Gandalf wouldn't even still be there, since he was only there to aid in the fight against Sauron. He'd have gone off to Valinor shortly after Sauron's defeat, together with the rest of the elves. And there'd be no Aragorn to be a good pal and extend the good lifespans of the realms of Men, so Gondor would never get a new king and the realms of Men would likely fall to evil a bit into the third age.
Would goblins/orcs still have endured without the lingering evil of Sauron?
They weren't naturally occurring (yes they bred but they were made to be a breeding army for evil and I'm pretty sure Tolkien alluded them to dying out quickly after the ring was destroyed) in Tolkien's lore I'm pretty sure and were interchangable terms for the same species in his lore even though they're different in others.
Would they have even gone on that quest without Gandalf pushing for it to happen? Wasn't Gandalf worried about Smaug helping out Sauron? Or is this the nasty Hobbitses films polluting my mind?
You know, there's actually another trilogy even better than Lord of the Rings that was never written because this exact scenario played out. You would have loved it, but the guy who killed the other guy really did everyone a solid.