I don’t think you will find any biblical references that there are no mountain ranges. Indeed, the Bible says just the opposite, that there was a mountain (covered by the flood).
However, the Creationists must explain where the masses of water needed to cover the highest mountain by 20 ft. came from. If the highest mountain in the world were say 6 inches tall, then there would be enough water in the Antarctic ice cap to cover it by 20 feet. Hence, Floodists like VERY small mountains.
On the subject of making “mountains out of mole hills”, I think the Floodists are working hard on a minor point, the mountains, and ignoring a much more significant point, namely how the same God who got disgusted with mankind and killed them all (save 8) is the same God would give his only son to save sinners.