If you want the game to be much easier, you really only have to remember one thing: When you get asked, "You wish to fight me?" (or something to that effect, new script), say no.
The game is pretty straightforward and it's usually pretty easy to tell where you're supposed to go. If you get stuck, there's an old man who gives you hints. As for leveling, you don't have to grind, but it's a good idea to not skip any battles. If you do every single fight, then you should be at appropriate levels for whatever bosses you run into.