Personally I don't think we ought to be scouting more quite yet, while it's clear it'll expand our knowledge of the world around us, I feel that it's better to expand our knowledge of the world directly around us, besides if the barbarian tribe doesn't know we're here, it seems foolish to seek them out until we're sure we can handle it, and while we won't find out whether or not that's the case unless we scout, I still don't think it's worth the risk yet. If they're much more capable than us, letting them know we're here will fuck us over, if they're not as capable as us, we were already safe. Unless we're suddenly going to try and get into war(which we've passed up basically every chance to be), it seems like a lose-lose option to me. We can already see anyone coming towards us from miles away so it's not like we'll be surprised if they try to attack us, we've got a great defensible position. Trying to go on the offensive against a tribe experienced in war seems like a bad idea. Scouting away from where the barbarian horde is would be a better choice for me, but even then, we might uncover a worse evil which we'll stand no chance against.
Attempting to get better tools is by far a better choice than scouting, but I still believe that if we're going to settle down in one area to call home, we need better food sources, we're not in danger of starving, or of failing to grow, but if something happens to the herds for whatever reason, we'll basically only have the river to feed at least 400 of us. Since we're near the river, it seems like the perfect place to experiment with the plantlife. If the stories of flying beasts are true(rather than the absorbed tribe talking out of their collective asses) then there could be more bizzaro-earth things closer to home.
Having even the first baby steps towards agriculture of some kind will start to make this place a permanent settlement, and once we have a permanent settlement, it'll give way to loads of other advancements, at least that's my view on it. Then there's also very basic medicine, poisons and like I mentioned, the possibility of bizzaro-earth herbs.
Failing that, exploring the mountain even more in-depth, attempting to expand our ability with tools somehow, or the quality of our tools, learning how to fully exploit the river, hell, even more animal taming seems like a better idea than scouting to me.
Whether or not studying plantlife is a better idea than getting better tools, I'm not sure one way or the other, but I'm fairly sure it'll be better for us than scouting more. Knowledge is power, sure, but that's a double-edge sword if we're discovered.