Two comments:
It took me a while to do the barrier because I went the other way and the only reason I turn around was because the spiders and orcs were just too darn hard for my party of level 9. I'm not saying that is a good thing or a bad thing; just a statement.
This game is a lot freaking easier if you have at least one character with high perception. High is relative of course and I will let you determine what is high enough.
