Referring to the Hills of Argh post, I'd love to hear more about the structure you've built for this campaign!
As briefly as I can so as not to derail the thread:
[sblock]Essentially just three locations (Tear of the Moon Goddess, Dragon's Grave, and The Tower Inscrutable) out in an abstract wilderness area that is chiefly forested hills. There's the starting town (Brownshire). The town is 15 miles from the Tear and the Tower and 30 miles to the Grave. It starts off as trackless wilderness (difficult terrain) and the PC can hire a team of laborers to create a trail for faster travel later (no difficult terrain).
Moving about uses the travel pace, distance, and Activities While Traveling rules. There's a random encounter chart from Xanathar's for encounters while traveling and resting (6 checks per day) which can be influenced by travel tasks and whether or not the PCs are on a trail. Weather is rolled randomly with extreme heat, strong wind, and heavy rain as possibilities which further influences how things play out.
The play experience is basically intended to be: (1) Create trails to and between all POIs; (2) Find the dungeon; (3) Track and kill the apex predator (which is a young red dragon in Hills of Argh, taken right off the random encounter chart); (4) Establish/defend an outpost near the dungeon so people can both start the session there and long rest there (as opposed to starting and resting in Brownshire); (5) Delve the dungeon. Once all those things are done, the area is considered "civilized" and the outpost can be expanded into a village, town, city, etc. which increases the radius of the "safe zone" where no random encounters are rolled.
Replayability comes from repopulating creatures in the three locations and dungeon as appropriate, again by using the random encounter chart. And the changing cast of characters that explore the area - not all the players or characters are the same with each expedition.[/sblock]
That's about it, we can start another thread if more discussion is warranted.