Looking back at my past campaigns, the ones I've had the most fun running (and which were arguably the most successful) were the ones where the PCs could take a fairly sandboxy approach to exploring a wilderness region. I'd like to develop a new campaign like this again one day, but what I could use for such a campaign is an interesting premise. I am ruling the following premises out:
- Adventurers plundering old ruins for profit: Too trite.
- Adenturer-archeologists uncovering the deep history of the region for academic bragging rights: A lot of fun, but I have done this before.
- Making the region "safe" for colonization and settlement: While the whole concept of "colonizing the frontier" provides plenty of interesting background drama for a campaign that I don't mind exploring, it is too ethically dubious to make the PCs take the side of the colonizers by default.
So, what other premises can you come up with that provide a justification for player characters to hang around a frontier region and explore it?
My current game might be helpful, but it will require a little context to explain and work to adapt to your purposes.
All my games take place in the same world. The last game was a pirate campaign, and, by the end, the players were legendary pirate kings (queens, nonbinary monarchs) that ruled the seas.
That leads to the setup for my current game: Sea travel is impractical and dangerous. A land route to totally-not-asia would be great, but none is currently known, due to a thought-to-be-impassible mountain range between there and here. The Explorers Guild is offering bounties on both a pass through the mountains and a viable charted land route to totally-not-asia. The players (and their rivals!) take a dangerous sailing journey around the mountains, to explore the jungle on the back side of the range and try to find a pass from that angle.
EDIT: They're incentivized to work with the locals, because pissing them off would make a potential trade route dangerous and therefore worthless.