The Disneyland monorail tends to get busy even though it doesn't have many stops. Ikspiari, Disneyland, Disney Sea and maybe one or two hotel stops. It's circular and there's a fixed price for all journeys. So if you're mad like me, you'll get on the train and wait for it to do several complete loops before getting off.
Please note that trying to sit at the front of this driverless train is not an easy task. It's worth it because you get to look directly out of the front and that's always good stuff. However, you're often thwarted by children, but, hey, I'm bigger than they are, right?