I agree with TyGI20. Unlike the path through the Paths of the Dead the path the fellowship took through Moria is well described in the books and so most people would like to walk that exact path to experience the fellowship's experience for themselves and I doubt they would like to constantly have to guess their way forward through the near endless halls of Moria. If you want to guess your way through you can just leave the path whenever you want and try to find your way through any of the literally hundreds other halls in Moria that the fellowship didn't go through yet we built anyways. The fellowship's trip through Moria is such an iconic part of the story I think the experience would be ruined by having to guess your way forward, not knowing for certain if you're actually following the path of the fellowship or not.