I might be way off, but the case of Brianne Wolgram:
http://findbrianne.wordpress.com/ - has a few similarities to the case of Leah Roberts in Washington State. Her car was found abandoned on a logging road in Revelstoke in B.C. I am not from the US or Canada but the areas are only about 331 miles from each other by road. I don't know if it is possible the cases are related but you never know, killers have been known to travel. Just a thought to put out there. I really do hope this family gets some answers from the DNA. I also think the clothes being snagged on trees, etc. is that it is possible the windows were open and as the car went over the embankment the clothes flew out? Or maybe the clothes were taken out by her kidnapper or killer to destroy evidence by leaving them outside the vehicle? It does seem like someone tried to stay there, but maybe she left her kitten in the car and went up to the road to see if she could get some help...hence the blankets over the windows? And she met with foul play when she went to ask for help?
Oh actually from reading further again it may be that Brianne might have been taken by someone she knew...it is interesting though that along that stretch you pass areas to the east such as Kelowna...towns that have had a few disappearances throughout the decade.
Geoffrey MEISNER - Kelowna
Owen Rooney - Grand Forks on way to Kelowna
Cynthia Frances Maas - remains found - Prince George
Patrick Lyle Boulton - Heading to Kelowna
Michelle DuRocher - Kelowna
I might be way off here, just interesting to note a few of the cases have cars with no body found in or near them and with damage to the vehicles.