General antonyms:
* Clear path
* Easy route
* Smooth sailing
* Solid ground
* Firm footing
* Open road
* Simple solution
* Straightforward process
Antonyms emphasizing ease:
* Simplicity
* Clarity
* Streamlined process
* Effortless journey
* Uncomplicated situation
Antonyms emphasizing success:
* Triumph
* Victory
* Achievement
* Prosperity
* Success
Antonyms emphasizing clarity:
* Clarity
* Transparency
* Certainty
* Definitive answer
* Clear understanding
The best antonym will depend on the specific context in which you are using the word "quagmire."