I would look up the two EBJ article with Scott Faimen ( In think that's his name). He hunts the Rubies successfully and not always by backpack. It should give you a sense of the area. Also, the old Larry Jones video How to Hunt Open Country Mule Deer from Wilderness Sounds was in the Ruby Mtns. They too "car camped" and hiked in each day to hunt although they underplayed this in the video.
I haven't hunted the Rubies, but I have hunted in adjacent ranges. I found that hunting from the end of a jeep trail without an official "trailhead" designation can be good and avoid the crowds. Good luck!