If you use auto attack then you're not going to get very far in the game. The only way you actually feel any grind in the game is if you're trying to raise a specific skill to very high ranks (such as windmill to rank 1; god that is such a chore) otherwise leveling and such do not matter. Dungeons give abundant xp and randomize maps so no two dungeons are ever the same.
I would recommend watching the vids or reading up on wiki before trying it out.