I did this at level 35 with questie gear and master Athlete. It was not too difficult but very time consuming. There are 2 prequests you have to do for Rouven (Tunnel Magics & Chronicles of Seyan) to get to Carlos Quest. Both gave me virtually nil experience. 15% of a level of exp at level 35 would be a decent reward. The 3rd and final quest in this line (Wanted:Occult Staff) takes quite a bit of time and must be done carefully as there are many hazards along the way to kill you. I received approx. 10% of a level of exp for this. I think 50-75% would be much more fair for the time and effort it takes to complete this.