Once you reach "the end" you don't have to hard reset to continue playing at the same difficultly, you can still reset as normal to continue. You just won't be able to see your banked souls or power, but still play normally otherwise.
If the monsters get tougher with each vet level, skill exp gain needs to be increased as well. Sitting at skill level 35 and getting 10 exp for a level 6000 monster that can kill me in three hits is pretty bad.
For those trying to get the BotD get gold on the first song, when you get at least bronze the other four another song opens up, get bronze on that one then pick one of the bronzes to play until you get gold on it.
For farming gold the monsters respawn behind you very quickly, so it's much faster to just run back and forth through the level vs. beating and replaying levels.
Done! Thanks for the feedback!