Technical Drawing Style - Line Art with two line weight

I design parts and assemblies in Solidworks.  Sometimes I am asked to provide line art for technical illustrations in manuals.  I bring the 3D cad assembly into a 2D drawing placed in a particular position.  I then output a .dxf or even a .pdf that I provide to the tech pubs people that they use with Corel or Illustrator.  We are thinking of starting to do our manuals with the sort of style where the line art illustration uses two line weights.   here is something I didn't create but found with a google image search for technical illustration styles.

https://drive.google.com/open?id=0B-lFPuPhG-viWnRtOTA2YW80WE0

In the example the whole thing is outlined but so are some of the features. I would mind a simple technique that can automate the selection of all the outside borderlines.  I can pick the few lines that are interior to that manually selecting them.

I think there are some expensive additions to Solidworks that can do this but I am wondering if there are some tricks in Coreldraw to accomplish this other than select lines by line or with selective windows across the outlines.  Making manual selection even more of pain I am finding with X8 that when i do select more than one line element with a shift select or with a window select I lose the line weight entry box in the toolbar.