I'm thinking of starting work on a game with a concept that includes mazes, boss fights, and a large world to explore...

Now! Does anyone know how I can make it work?

I think I got it though, 

If I can  create an isometric world, maybe implementing a 3d world would be easier. Now for a game to use as an example...

honest speaking it is too big, have many people you have? It won't work if you are alone. Trying think small because of the restriction of resources.

Without knowing what you're going for exactly, the large overworld map in Super Mario Bros 3 can be a good inspiration for how the player can quickly transport between sections. Early Zelda games also have good ways to, basically, teleport around the map, which you'll probably need as the scale gets bigger to stop the player constantly trundling through the same sections.

Saying that, I'd always try to make sure the screens are interesting and do a lot of work. Better to have 4 screens that are always evolving (based on character triggers, time of day/ seasonal  cycles, items/ money that can open up different sections, NPC activity etc. etc.) than 100 screens of boredom. Again, the early Zelda games are a real masterclass in how to do this well.