Quality of Life V15 is required to use this mod. Just download the zip, unzip and add to the patch folder in the mods folder of Vermintide's mod directory. This mod changes the random button on the mission select screen to always choose the Trials of the Foolhardy mission, even if you have not unlocked it. This should help solo players or groups of 2 or 3 missing the crucial 4th person. If you complete the map on any difficulty it will be unlocked permanently and the mod can be deleted to return the random button to its original function.