It should be a fairly simple question, but it isn't, because of the number of expansions which give you special tiles and special 'abilities'. Many people don't use the builder at all because the double turn it enables is 'unfair'.
AFAIK, the situation at the moment is that play ends when ALL LAND TILES have been played. You don't have to make sure everyone has the same number of turns. But if you have, say, an unused Abbey in you hand at the end of the game, you aren't allowed to play that.
I have a sneaking suspicion that RGG is a little different here, but the ALL LAND TILES rule stands whatever.
Incidentally, the question of who starts the game is just as complicated