I remember in early Planet Coaster, the different biomes were sculpted. One of them was really cool, with caves everywhere, and a huge drop off
I'm fine with the flat areas, but I wish we still had the pre-sculpted ones as well.
I think these were like the early scenarios in the alpha. Most made it into the career mode. I think the one you are taking about is there. If it is you could convert it to sandbox. There may be pre sculpted ones on the workshop. Though I haven't looked myself.