I have noticed a lot of people running at L16 as a result of the Stone of Leveling. They are running a lot of quests at or near their levels but without really any experience on characters in this level range.
One quest that I've run with some of these players is Crucible.
Crucible is one of the easiest quests to run if you are prepared. It is a nightmare if you are not.
First, a rogue or monk with improved evasion and a high reflex save is a must. I know that people say you can get by without them (by being a superior player) but for the normal group this is a must have character. Reflex save must be in the high 30's. Trap DC's are around 40. Normal evasion is fine if the character has lots of HP. But, the traps hit for 200+ damage and in the swim portion of the quest they are packed closely together. So, improved evasion is better.
Second, make the rogue or monk do the evasion parts of the quest. Do this even if they have never been in the quest. They have to learn it and that is the only way.
Third, for the swim part the swimmer needs to be the evasion character and they should have cure or repair potions. If they're lucky they make all their saves. If not they should top off before swimming further. Potions work underwater -- wands and spells do not. Waterbreathing isn't needed if you have a high swim. Since most characters do not, it is usually needed.
Fourth, when it is time for the maze do it the easy way. Since the maze is the first obstacle to overcome you need to know how to run it. Look at the Wiki to see the general layout. The map there is not perfect but it is close enough that you can work with it.
To run the maze do these things:
1. Go to the I valve first. This is the fastest way to complete the maze. Take the whole group. Turn I once and go get the first crest. Have one person go to I and the rest go north to the I door. Turn I a second time and go get the crest. Leave the alcove and turn I a third time. Go to the east side door and place a crest, then take the whole group to K.
2. Leave 1 person at K. Take the rest of the group to the K door on the southwest side. Turn K and go thru the door then stop. Turn K again and go get crest. Head towards the H valve.
3. Leave 1 person at H. Take the rest to the H door in the north west. Turn H once. Go thru the door. Turn H a second time. Go south and place a crest then go back north. Clear as far east as you can go.
4. Go back the way you came. Turn H a third time and go pick up the H person. Continue going back the way you came. Turn the K valve a second time. Go thru the door. Turn K a third time and go north placing the last crest. Turn K a final time, everyone go to the middle and thru the east door to I.
5. Rogue disable traps and get horn, then go thru east door. People at I turn I one last time. Head north out of I to the north east corner and the exit. If no rogue have monk grab the horn.
If you practice this it takes less than 3 minutes to run the whole maze. There are other solutions that let you out the north exit from the center. They take turning the H valve one additional time.
You can also get by with turning K only 3 times if you go out of the maze and back in from the south east. But, turning K is faster.
Once you know the maze you can do it very fast. If you have good evasion characters along then the rest of the quest runs smoothly as well.
One last bit of advice. Use diplomacy on Vrall and Daggertooth to start with and get the map. With the map use intimidate on Gorn. Then go back to Daggertooth and use bluff. Finally, at the agility challenge use diplomacy on the kobold. A 22+ in each skill gets you thru all of them. It is easy bonus XP.