i think if you maybe use a garden hose with a screw driver butt at the end it will bounce off any snags. i used this method on saturday to feed a tank breather line through the water drain in tray of VS ute. with the beaver light I imagine you might use a coat hanger from the outside then attached the beaver light wire and pull it back out??

i think the snake would work best and they are cheap but it's all about MacGyver style improvisation for me