Wooly Rhinos in a den? Too funny. That's what you get with all the procedurally generated stuff.
And that's my dilemma. You've got good ideas there and I've noted them down. My choice is to create, say, a "dark fey grove" generation routine and have them generate as a type of random feature. Or to custom craft a specific "dark fey grove" in one location. Generation is good because you will get them all over and are more likely to run across one. But it's bad in the sense that once you've seen one, you've seen them all. Even if I make them varied there will be still be a certain "sameness". The alternative of hand crafting is great because I can do very detailed and custom content that tells a real story. The downside is that I can only put it in one location and have to put in signs and rumors pointing to it so that people can discover it. It's not always easy to work out which direction I should put the effort into.
Castles. So, the best thing is to first find a location. Somewhere that you either note the longitude and latitude of, or that's a known distance from a known landmark. Once you have picked a spot, use the "entry" land deed. That will prompt you to confirm, and WOOSH you should have a one room castle.
To expand, enter your castle. Pick another deed of a room that you want to create. Use that did. You will then be prompted for a direction. Give a direction and WOOSH, that room will appear in that direction. You now have a two room castle.
Keep going and flesh out your castle with what you want. It is going to be kind of linear because you can only extend from a room you already have. If you want to cross connect locations you need to use the mark permit and a door permit. Go to the first room in your castle that you want to connect. Use the mark permit there. Then go to the room you want to connect that room to. Then use the door permit there. WOOSH, those two rooms should now be connected.
There are also one way door permits, and doors that only let certain level characters through. You use those on existing doors between rooms to add more interest. Be careful, though, because you can cut yourself off. I haven't got the logic in there yet to warn you when you make a closed loop. If you get stuck, let me know and I'll sort it out.
Oh, if anyone here is a you tuber, or a podcaster, wrapping up some of these guides into podcasts would be super wonderful. I'd promote them as much as I possibly can!
Progression. I really don't like the idea of progression in games. The first versions of 6 Swords had difficulty firmly tied to how far you were from the road. That was more realistic, but, unfortunately, resulted in more boring game play. The monsters you met along the road were really just nuisances, and you had to hike all the way into the mountains to find anything interesting. So, reluctantly, I changed it so the monsters get progressively tougher as your team gets tougher. You can think of it as that as you get stronger, the lesser monsters don't even bother to come near you, and we're saving you the trouble of continually running away from tough ones.
Monsters scale in terms of numbers. A goblin is always a goblin, with the same armor class and hit points. But at low level you might meet them in single digits, where at high level you will meet dozens of them. And, I tell you, there's little as fulfilling as having six character fight a hundred and something kobolds and to wipe the floor with them!
Bounties don't scale, however. So it's probably a good idea to collect them as early as you can. Eventually you will be meeting monsters with enough money that the bounties aren't all the exciting anyway.