We enjoy the original TtR, but for two players, you both can pretty
much play games of solitaire. If you do want to play the original TtR
with two players, you might try what we did: After you have both
selected your destination cards, but before game play begins, select
two destination cards at random from the deck. Using a third color,
populate these routes with the most direct route possible (the number
of trains in these routes should match the values of the destination
cards), then remove these two cards from the game. Play now proceeds
as normal. With the two routes already taken, there is a little more
"competition" on the board.
Dave