Regarding bad roads: Where I used to work, I drove a mountain road to get to my assignment. That road would sometimes be impassable from either snow or falling rocks. They used to have one of those freeway-type lighted road signs with changing info. (like the signs used for missing kids) which clearly noted road conditions. They warned people of snow, rocks or the road being closed part way up due to never-ending repairs. The alternate routes were many, many miles out of the way, but we would gladly go around if we knew to expect problems.
If there are so many lost people on the road the Kims took(not an issue on my road due to no side roads to speak of),that type of sign might be best, though probably astronically expensive. With all the boondoggle grants out there and pork projects, their congresscritters could probably get some funding.
It sounds like a good idea to me.
You could put up a huge number of signs and maintain them for what one SAR costs.
If they average 80 per year in that area, they could be spending probably 1/4 that many millions a year depending on how may choppers and other sophisticated equipment is used as well as how many men.