I have a different point of view for crawl spaces only...
You do not need running boards for NM in a crawl space. You also do not need to drill or punch throuhg the TGI's in a crawl space. Stapling directly to the bottom of the TGI is perfectly acceptable in a crawl space.
Most TGI's have specific rules from the manufacturer and by building code allowing placement of non pre-punched holes in TGI's. In other words, drilling your own hole may weaken the TGI, and is generally frowned upon.
I would recommend stapling to the bottom - fastest, safest, yet still code compliant method.
Please note that this view is shared by all of the AHJ's that I have ever worked with. This view may not be the case in your neck of the woods, so I would check with your AHJ.