W. Eric Martin
So for example, if I have a route 4 I can either close the route for points or take a risk in hoping I can add one more card to my route on my next turn to make it 5 routes. If I don't have the card that I need, then I lose this 4 route and get no points!
Marco, you understand the rule correctly. Ideally, you will already have that fifth card you need in your hand if you plan to build a five-card route, but sometimes you have to take a chance. Since you can clear the board at the start of your turn, you'll have access to 13 cards total (6, then 6 and the top card of the deck), but even then you won't always get the card you need. Plan ahead when possible!