I believe that writer's block is a matter of fear and trust: fear of trusting the frontmost words in your mind and putting them to paper, fear of mediocrity, fear of failure, distrust of your ability. Trust whatever your muse gives you. Trust yourself & your ability. Trust the first thing in your head.
This is what I do:
If the end of your story results in your characters discovering the lost continent of Atlantis, then how are they going to find Atlantis? A mystical method of navigation--a magic compass. Okay, they need a magic compass. Let's take them to go find that magic compass. That's where the immediate plot needs to go. They'll need a boat to get there, but we'll worry about that in another chapter.
Maybe the king's cartographer or grand vizier will know, or perhaps the creepy old hermit that lives in the forest outside of town, everybody says he knows magic, so he might know about things of a magical nature. We'll say it's the hermit.
A HANDFUL OF GOLD coins clatter across the bar. Caught in the act of polishing the bartop with a rag, the bartender looks up from them, a bit startled. "Well, uhh, hello there. Welcome to--"
"I'd like to ask you a few questions," growls Character.
The bartender smiles. "Questions are free," he says, pouring a tap into one of his frosty mugs. He's a bit shouty, because the tavern is a bacchanalia of singing, stomping, laughing. "A sample of our finest ale, that'll cost you." He plunks the mug down on the bar and slides a few of the coins into his apron.
Remember, you're not working toward the end of the story. You're working toward the next step of the story. Eat this big ol' story sandwich one bite at a time.