bikers(the gay ones not the vroom vroom kind)

[Jeffrey Lebowski]

Good point, I hadn't thought of that. Is it a big enough issue that cyclists need to ride ON the white line or in the driving lane?

In some spots it is, sometimes it isn't. Some spots actually have chatter strips on the right, others have a lot of ground glass and whatnot. Even dust can suck. OTOH, sometimes it is pretty clear and cyclists are just being oblivious or intentional dicks about it. I can't condone that.

Of the canyons mentioned - my favorite canyon is Golden Gate, just because of geographic proximity to my house. There is no shoulder on that the entire way from 93 to 119, but it also isn't heavily traveled, so taking that balance I use it a lot. I try to ride just to the left of the white line there, but on the downhills, I'll take the middle if I'm doing the speed limit or better. If there are cars behind me, I hug as close as I can and try to wave them by if I have better view ahead than they do. FWIW, I've had minimal drama up there and I've been riding it for years. Also, FWIW, heavy trucks are never scary to me, you can hear them forever and get over - it is the "superbikers" who think GGC is Isle of Man TT or something that scare me.

From what I understand from limited reading of the laws they are considered a vehicle and are supposed to follow the same rules as a car, signals, etc. so they can legally be in the same drive lanes for a care such as a left turning lane.

With a key note of not "Impeding" regular traffic.

Bikes should share. With the most extreme of caution I'll "lane split" -but in a way to make my intentions obvious - and you hit on the when it happens. Turn lanes and what-not.
In the the case of a left, I'll (personally) share the left turn lane, but being on the right side of the left-turning car. I'm going to go slower (theoretically, if not always in practice), I want to be farthest out so I hit the bike lane on the cross street to the left of us. In the case of an intersection where there are two forward lanes (one for left, and a shared for right/straight), I'll share the right lane but be to the outside (left side) of it when I'm going straight so I don't get run over by a car going right. I'll carefully go straight and get over to the right when I can. Double left? -Really not a good spot for bikes. Find a better way.

But the point is, you also can't be cruising over onto the sidewalks and navigating intersections like a pedestrian either. Just be careful, obvious, and signal to everyone. I don't know that I've ever got yelled at in one of these cases.

Scooters fall under motorized bicycles and are not legal to be in zones above 35mph

I can't comment on scooters at all, but I'm not sure about this 35mph thing and bikes. In fact, I'm sure opposite.
A great example is I-70 between the Buffalo overlook/Genessee Park and Chief Hosa or whatever in Evergreen. This little stretch of interstate (!) is bicycle legal and marked as such.
That is for the most special of occasions only. I've only done this a handful of times in my life and don't really advise it for cyclists.