Civil 3d road construction with LIDAR data

I have constructed the road corridor and it turned out well, however when i select the TIN surface and the road corridor it does not look good. The corridor falls under the TIN surface in some locations because the road profile calls for a cut in the ground.

here is an attached image to show the problem

Is there a way to combine the two features and create a new surface which doesn't have the tin over the road but instead both features and true and visible. Basically remove the area from the tin that falls on top of the road.

And my second question is there a way to render the surface so you can add different effects like water, trees, grass.

Your tin must be bigger than your road corridor even if you dummy it up which is not recommended you can not calcilate a level where you have nothing.

Yes you can combine two surfaces just create a 3rd and "paste" the two together use the 3rd for design

Yes you can render road simple answer to simple question what to use and how is another answer all together others will probably answer. Watch the clock tick though.