Get a heavier bolt...seriously
Ive put lots of cables in insulated walls with the method I described. A heavy bolt or washer will slide down the wall between the sheetrock and insulation facing with little difficulty.
There are sometimes problems, things like cross framing and super tight insulation. I have a five foot long drill bit that I got at an electrical supply house. Its flexible, so its possible to drill a hole right through a cross member. It also has a hole near the end that will let you use it to attack a cord so when you pull the bit out the wire comes with it.
Its expensive (approx. $35), but sometimes there's no other way short of removing the wall.
