I play around with the Garmin G-1000 trainer for the Cessna Mustang a lot these days. The trainer is a genuine nav trainer with the actual terrain modeling for TAWS, and it has a worldwide, albeit out of date, nav database. But, not that far out of date for OPRN; i.e., the datebase is late 2008 and the last Jeppesen revisions for OPRN are dated in 2006.
Also, the G-1000 in this version has synthetic vision.
This is not a desktop toy, but an accurate representation of an airframe certified system.
All coupled up I arrived from the south and flew the ILS DME Rwy 30 procedure down the G/S to 2510, msl, then at the appropriate place I departed the electronic guidance to the right on heading and altitude at 2510 to do a circle-to-land.
I also entered "direct-to" to a waypoint I had constructed to represent the approach end of Runway 12.
I flew 40 degrees to the right of the LOC until I felt I was in a position to turn left to a runway parallel heading. This was at about 2.5 miles on my Runway 12 waypoint. I then charged onward. Everything was fine at 5 miles, but of course I should have been turning left in time to remain within 5.2 miles. Since I didn't I was headed towards the nasty terrain on a heading of 296. The TAWS woke up quite loudly at about 5.5 miles. The terrain became more detailed on the synthetic vision, and at 6 miles yellow became red. The crash was at 7.2 miles.
Chilling, but very informative.