workflow to create OVERALL proposed terrain

I am looking for best practices to create an overall proposed surface from mulitple corridors and 3D elements created in a "site" fashion.  When I attempt to create using just the 3D graphics using terrain from elements, I always get errant lines that aren't picked up or vice versa and I want them to be.  

We tried to be very careful in point naming and feature defs in our corridors, but there are always some error as multiple users have worked on this larger project.

Is there a way to save corridors to final top mesh like there was in V8i?  I don't see where I can do that anymore.  

I have searched this website, and I have seen the question arise, but have not been able to find any realistic answers to a good, efficient, accurate workflow.

Thank you,

Katie Wade