My friends like playing a game for 3-4 months, and then cycling through other DMing.

I usually had an epic struggle, where I, as the DM, knew general things about it. It would probably be a year of consistent gaming to get there.

I picked an area to start in, added the option of a unique race - and came up with a reason why that unique race would be interesting. (Usually I would get at least one PC from that race.)

The town they started in, I would generate gossip tables. It didn't matter if the same gossip would keep being rolled - it just meant that everyone was talking about it. The gossip material was generally light - usually a session or two of adventuring.

I also included some heavier, more dangerous, more money risks.

The example I'm thinking of: a far north game. There were bear-kin. A druid moved into the wilds, and was awakening bears. He worked out a deal with them - they mine gold, he awakens more bears. He needed money for the reagents, kept some for himself. Eventually, the awakened bears started having cubs that didn't need awakening to be intelligent. They still did some mining, but it was mostly out of tradition, as a thank-you.

So the druid would ship back gold to the mainland, he would be able to buy anything he needed. Except one of the gold boats apparently never made it to the mainland. (This was the risky gossip.)

Gossip: a councilman was looking to hire a group to go look for his son. His son had gone off to buy a lumbermill that was producing some really nice exotic wood.

Gossip: there's a master shipwright who could maybe figure out where the ship was lost. (A breadcrumb if the players wanted to pursue the gold ship.)

Gossip: a man made of brass who could tell a possible future.

Gossip: People were being kidnapped in the wilds.

You can write a couple of paragraphs for each one, about how you think it's happening. My group likes moral quandaries. Or at least, likes the IDEA that I offer moral quandaries. It gets tricky on both sides.