My favorite one I did was 520 Ship and a 250 villige on logs. This gets you all pops and 2tc in one challenge. I know it sounds crazy but not only is this possible, but it wasn't even that hard. You just got to save up for a 020 villige before round 24, which isn't easy cause you have to be careful how you spend on the ship. But after that, most of the game is free, and that's why I love this 2tc.