I'm not sure how it happened but somewhere along the line I diverged from the main quest storyline and ended up spending a week travelling around the game world from town to town doing minor quests and going up in level. Then just last night, I decided to head back southwest to the desert to tool around there and suddenly found my way back to main quest again. All of this completely by accident.
All I have to say is that it's an incredible game to be able to go off like that for (in my view) a long time and still be able to play in a somewhat satisfying (if repetitive) way. Although, I'm glad to have stumbled upon the main quest again.

The game rewards ridiculously long grinding sessions with a boss fight, for a chance a treasure and unique items. Just be sure to remain in the same "region" if you're going to do this, for if you leave a "region", the counter resets.