No effect whatsoever. Events like that occur at fixed dates, rather than at random. If you don't want to "hack" the game, as you put it, and you don't want to win the game before the New World is discovered, then just get to a certain point and turtle up. If you decide to do this, then I recommend the following course of action to you:

1) Give Jerusalem to the Papal States. Holding it will entail a lot of work and expense. Make nice with His Holiness and let him deal with it.

2) Make sure you own the entirety of the Iberian Peninsula, but stop your expansion at the Pyrenees Mountains. This will give you a natural and easily defended border.

3) Take all of Africa. There is an impassable land barrier in Libya in this game (unless you're using a modified map) so only sea invasions would be possible.

This will leave you with a large and fairly profitable empire without putting you so far in the lead that everyone is likely to hate you. You'll need to control bandits in Africa, defend your border with France, and defend your island territories, but you should be safe there.