Board Game Arena

I'm curious about the objective of having the longest river. Does it only count the river that is one continuous line like ticket to ride, or does it count all the river that is connected?

I don't see where the 2 player variant rules come from and didn't find them in the English rule included in BGA. I just play a 2 player game, and from my observation, the 2 player rule change from draw one face down card from the deck to choose between one of 2 visible card. Once the player run out ...