It is an interesting viewpoint that you've taken here. I'm trying to look at it from an ecological impact POV while still putting the Skytrain through an area that will benefit from the transportation linkage.
(I'm sure there will be rolling eyes going "Oh...God, here's one of those damned "tree-huggers"!!) Unfortunately, for me, the King George Skytrain route that you have put has come uncomfortably close to the "Serpentine Fen Migratory Bird Sanctuary". Loud noises such as the Skytrain's wheels on the rails can interfere with the birds at that sanctuary. Perhaps a detour through 72nd Avenue and down 152 straight down towards White Rock might perhaps be a better route.
http://www.venturevancouver.com/image/serpentine-fen-map-of-bird-sanctuary

screencap from Google Maps.

Wikipedia Commons attrib. Creative Commons.

(my image) - photographed by Haruo Chikamori (me), FalconRose Photography.
The proximity of the Skytrain would be way too close to the sanctuary to be viable. It is a two lane highway going down King George and there is no leeway for Skytrain pillars without Serpentine Fen being affected. And the ALR is on the opposite side of the King George Hwy.
Any attempt to put the Skytrain through King George Hwy. will cause an deafening hue and cry from the local wildlife and conservation people.
The viable option is 152nd Street.