Getting to the end of the bad end dungeon is (supposed to be) about trial and error and learning the timing of the enemies/hazards. This takes time which I can see that some of you don't want to spend.
Probably the easiest way to cheat at most of the puzzles would be install the
RPG Maker Cheat Menu plugin and use the No Clip toggle, which will allow you to walk through walls. That plugin also has an option to reduce Enemy HP to 0, which should defeat at least some of the random battles you shouldn't be able to win under normal circumstances. Just remember, even if you reach the end, the dungeon cannot be escaped...