The only guidelines we have for the No-Shortcut category is that you're allowed to cut cone sections. Is there a limit to how far you're allowed to do that? And what about other sections that may be less obvious, or other places where there's some fairly innocent (and potentially intended) cuts.

I uploaded a few example images here: https://imgur.com/a/Nlndomj.

Skipping Loops:
Attic Trouble First Loop skip: From this jump, boost fly through the middle of the loop and land directly on its exit.
Dangerous Perspectives First Loop skip: A less advanced version of the previous one - here, all you have to do is slow down and drive off the side of the track piece to land on the exit, rather than navigating the entire loop.

Swapping Branches:
Attic Trouble has two examples of that. Taking the first branch left, there's plenty of ways to land off the big jump on the other branch and skipping what would otherwise be an unnecessary track extension. Taking the second branch right, the branches make parallel leaps towards the end, but the left side again has an unnecessary track extension that can be skipped by trivially jumping to the other branch instead.

Cone Cuts:
How aggressively will those cuts be allowed? For example, Bridge Overtakes between CP2 and 3 has the cones go out for another few inches before cutting back, but the standard shortcut route through here is to just apex around the chair leg. Is that cut actually allowed for No-SC as well? Similarly, Ready, Set, Go! has a major cone corner that goes around another section of track, but that section is raised where you could just drive under it. Or you could potentially just jump across the other section of track since that's still kind of following the route the cones suggested.

Just my 2 cents (whatever that's worth lol).. Doing some crazy boost flying to skip half the track and just hitting checkpoints is probably considered a SC. Driving the whole course the way it was intended on the other hand is considered a NoSC.
Cutting cones should be allowed in NoSC period.(imagine you losing you're run because you drifted outside a cone a little)
As for the loop dilemma, I think you should have to drive the track. Falling off or boost flying to skip three loops I think should be considered a SC.
I did a run in Attic Trouble and boosted off that ramp to land on the other portion. I don't actually think it saves that much time then just driving the track the way it was intended. I left it up to the mods to decide whether that was a SC or not and they chose that it was not a SC. (I'm completely fine with it if general consensus thinks that is a SC and I'll redo that run.)

I think the major difference of SC and NSC is anybody can pick up the controller and record a run for NSC. There is ultimately no learning of boost flying and flipping off the track.

In T-Rex in the Living Room, I found that you can clip off of a flag after the first ramp, and with enough speed, can make it to the track on the left, landing by the roof. You guys gotta see it in my run of the track. The link: what I wanna know is if it counts as a shortcut, cause you're skipping some of the track, but not any checkpoints.

I meant loop.

The no shortcut category requires you to go through every single piece of track (offroad excluded), here you would effectively ignore a small section of the track which makes it a cut. So yes.

If you're unsure as to whether something is ok or not, you can check out the current no shortcut runs for a track and see what can and can't be done.

Ahh, so that 1'40 would fall under the sc board. idek if I was the first player to discover it, even by accident.

It's a known tech that wasn't applied for this case, a better strat is known anyway for this track so it wouldn't be useful.

Well, it's still surprising that it's possible, cause I landed it a few times.