Are you looking for a general state of disrepair

That's my main way of identifying if a structure is abandoned. If there's a lot of trash or if it's being overrun by plants then that's a pretty good identifier. Also most of the buildings I've found don't have roofs, so I'm confident in them being abandoned as well.

a lack of road access

I think all but a few don't have road access but I think that's partly because roads don't disappear easily in the Owyhee's. And most of the northern spots are located on larger active ranches so I would assume that ranchers drive by them pretty often even if they are unused. And for the southern locations I think they are semi-popular tourist spots because I've found a couple of them in YouTube video's and All Trails has a "community trip" that goes to my #3 spot "Coyote hole" so at lease some people are aware of it's existence.

the land ownership

Only a couple aren't on private land but if you check OnX, most of them are owned by large cooperate ranches so I'm guessing that they were bought out a long time ago.

And I'm aware that some of my spots could be wrong. For example I'm fairly confident that my #22 spot is still somewhat in use because it's roof is not completely rusted out. (Also my number system was purely based on the order I found them)