I lockpicked the door to Loic's secret area which takes you to Sacred Stone. I also have an amulet to gain entry.

Is there any reason to do the trial? Does it give a good XP boost or any good items? I seem many people complaining because of the difficulty.

Just do it.

The majority of the trial is puzzle--which is annoying/hard/challenging/pick-a-word-that-describes-your-relationship-with-tough-puzzles here. But if it's too much for you, just watching a vid tutorial and bomb it out in five minutes. There is a fight in there, too, but that's what the game is, right? Puzzles and fights? I'd say go for it.