A lot of people have different ways of developing. Odds are the preference for a smaller project is due to the fact that you are new to the RPG Maker series. A lot of people have all these good ideas and they wish to create a fantastic game with it but then dive into it and end up going through a lot of technical troubles because there's a lot more to it than you thought.
You could always do a smaller prequel project just to learn and get an understanding on how the system of RPG Maker works and later create your bigger project. That will reduce future problems you may have with the larger project.
My recommendation is to plan out your entirely large project and start with that first. I like to actually work on my large project and then after I am finished with the project, I go through the testing and then have other people test it. When everything is sorted out, I create a brand new large project that is exactly the same as the first but more simplified, more detailed than the last, update the graphics and test it more. Because since the first one is set up, you already know how it will look so you just create a newer version and polish everything up. After all of that is finished, you can create additional content to continue to expand the game.
