Actually it does reach a point where you cannot get back in even with lockpick level 5. I broke that quest one time through the game because I forgot to get the cure potions from his basement the first time I was there, and could never get back (even though Elrath had already been turned in).
The quest is good rep and exp, but not critical to the game, so don't spend too much time worrying about it <img src="/ubbthreads/images/graemlins/smile.gif" alt="" />
