I was thinking that Steelbeck would have a 'General' idea some things lessening this.

First, he flies and is pretty arrogant about it, so I doubt he'd just blurp out these things, if anything his geography insight might be more vague and relative to give a position compared to how far deep you are: "There's a mountain there, a large stone structure here so we should be around here on this completely blank map, distance wise."

Second, for Irony's sake I think he'd say 'Don't do anything, don't drink any water, don't eat any fruit, my people were dropping like flies the moment they started eating and drinking stuff here, however I'm not actually a trained to say what actually caused this.'

For the ruins the key thing would I think be that he's seen one of many and although he could see paterns and give tips like "There are generally traps by this point." or "I don't trust them, I saw tribesmen make sacrifices to their gods once". Because after all he may have seen SOME things, he would be far to have seen everything.

I thought the deers were somewhat new to the political landscape? So they were already part of equestria the moment Twilight laid eyes on them? That would have been the point: Conquer the unknown land before Equestria decides to annex it. As for where they went, some of it stayed back to 'Occupy', meaning flying above the wild while occasionally fighting with deers, while the rest would have just 'Gone south', but with little navigation expertise, have actually just got lost after 1 year, gone around for 1 to 2 year and spent the remaining time trying to figure out how to go back for the rest of these 4 years. The point is that they found almost nothing worth of interest and Steelbeck was ruined when he came back.

Basically, I think you know I'm not a dick so use this as a plot device. For all his background says he might have run into ONE ruin. He's an expert, because no one else ever did, but I think there may be more, much more in there. If you say as a GM: Steelbeck, you know what's going on here, then fine I will tell of it, if not, Steelbeck will just be an arrogant dick acting like he knows all that's going on but actually doesn't.

The final judgement however, is yours.