No takers? I had hoped for some bludgeoning, George
To sum things up as they are known so far:
You are looking for a feature in the Solar system. It is "all about being below its surroundings", so some form of depression; it
named after somthing "all about being above its surroundings", so some kind of elevated feature.
A mythological figure had a strong incentive to get to this place (the elveated feature) for unfinished business. That I described the figure as a smart-alec hints at two facts: He is smart, and he is not necessarily loved for it, otherwise I wouldn't have used the slightly derogatory term. In fact, some people hated him for his smug cleverness, but all respected him. And - hint hint - he was, in the end, a very successful man. We also - hint, hint - heard the word "travel" in connection with him.
I think this is not unsolvable, frankly. I'll add more hints as time progresses (hopefully, it won't for very long).