Put the sign '100 miles to Godville' in the proper place
The quest "Put the sign '100 miles to Godville' in the proper place" is a moderate, not quite expert level of difficulty quest. It was previously rated at a difficulty of 1/10; until a group of heroes who had died trying it petitioned for a higher increase to reflect the trials and tribulations they had endured in order to accomplish it.
There are three things to get straight before we look at how difficult this quest is. First, heroes need to be able to locate the sign in the first place. Generally speaking, heroes need assistance with this portion of the quest 99.97% of the time and this no actual progress can be made in accomplishing this quest until the sign is located.
Second, heroes are always in a hurry and thus unable to take the time to read the sign to know where it goes once they have located it. As a result, they struggle with this quest and will refuse to stop to ask for directions to make sure they get it right. The 100 mile journey out of Godville to place this mile marker is often dangerous or at least moderately boring.
Third, taking a mile marker from one place to another takes effort and skill; which we all know the hero usually has neither. Finding the exact location once you get to the destination can be tricky, but with a proper post-hole digger the hero can put the sign back where it belongs thus successfully completing the quest. If they set the sign down anywhere along the journey, they will most likely have to go all the way back to Godville to request a new one. It is a well-known fact that some heroes do not complete the necessary documentation to request their Godville marker, and actually set out on the journey of completing this quest in the hopes that some other hero has accidently lost their sign - saving them time, trouble, and at least a few milestones of travel.