Early on in the iron era, exploring is a catch 22. You are unlikely to spot crypts from a safe distance at sea during the day, and at night the lights you see may be misleading. So you usually place your bet on the biggest swamp you find with a nearby 'safe' access point. Then after investing in building a port/outpost, you find all sorts of things.. possibly including a nearby but hidden plains biome, but not a crypt in sight. You only dare fight the lowest of the low and night explorations are suicide, so you cautiously push the boundaries, explore, and in the end, find out that this nice big chunk of swamp has not a single crypt.

The only win in this scenario is not dying, or at least not dying where you can't retrieve your stuff.

This was fun, for a certain definition of fun, the first few runs, but after 2000 hours.. three tries and I summon the world generator, lol.