Well, I can confirm that I did find Faucheuse. I think it was actually the first of the various "treasure hunt" type things I discovered, but as it turned out I'm glad I forgot about it for so long before finally getting around to following the clues, because it was the most difficult of them. It was quite a journey. Goes a long way into territory that's much more dangerous than where it starts. Feels like actual map reading skills could be useful. Very satisfying, if you enjoy that kind of thing. The path does go near some obviously unfinished areas, of which there are a few scattered across the land.

As the fights got more difficult, I relied on alchemy quite a lot. Also paused to spend some time levelling up smithing a little, by practising leather working mostly. Lucky for me I'd set the crafting skills to level at something closer to a normal rate compared to everything else, so they wouldn't be too grindy. Very good weapons can be found, but you'll probably want some decent armor too if you want to feel comfortable in such places as are found in for example the Hall of the Mountain King.

Even with a whole lot of time spent improving skills and equipment while wandering around, I found myself running away from things at least some of the time all the way through to very near what seemed like a sensible place to call an end to this Chanterelle playthrough. For now I'll be off to spend some time in Skyrim for a while. The next playthrough will start in Chanterelle again.