Eating well the night before a longer ride isn't nearly so important as eating well DURING a longer ride.

It is good to eat a decent meal the night before a long ride so you aren't depleted, but you don't have to overload yourself.

As for food selections for the night before, go with bland stuff that you are used to ... things you know won't upset your digestive system, such as chicken and pasta.

Even more importantly is to keep eating while you are riding. Consume about 250 calories per hour you are out there, and then every 6 to 8 hours eat a full meal of at least 500 calories, preferably more. On a metric century you won't likely be out there that long, but if you start increasing your distances you will.