Combining spot elevations and LiDAR contours

I have been using spot elevations--gathered in the field-- to create terrain models in SketchUp, using the 3D connection. 

Now I have some contours from LiDAR that I want to add for areas that are outside of the area we surveyed. Is there a way to combine those two types of information? I was going to simply add some more spot grades based on the LiDAR contours. Just wondering if there's a better/different way to do it.