Before my last campaign ended due to out-of-game issues, I had gotten the party to the city of Riftcrag, perched on the edge of the mighty Rift Canyon. The plan was to get them involved in the exploration of a warren of tunnels and dungeons dug into the sides of, and running beneath the floor of, the canyon itself. The major dungeons were to be connected by tunnels, laced with minor encounter areas a la D1-3. The dungeons were laid out rather linearly in terms of accessing them through the tunnels, but it would be possible, by finding secret passages and so forth, to skip ahead as it were (and also skip some of the potentially dangeous minor encounters).
One of the tricks was that the dungeons could not be easily found from within the Rift Canyon itself, which is riddled with caves so that years of exploration could fail to find their entrances. Once you found the exit, however, getting back in would be easy. Thus, the players would have to start at the beginning, but could make their way back to Riftcrag for rest and recouperation, and then rejoin their explorations of the whole where they left off. The encounter areas were designed so that they could start at level 1 and then work their way up as high as 15 or so; each major encounter area being designed with that power-level in mind (analogous to the idea that deeper dungeon levels have badder monsters; the further away the characters get from the Orc Tombs, the harder things get). Naturally, that makes skipping encounter areas via the secret passages somewhat problematical…
I hesitate to put forth any details, just in case I end up getting to finish designing and then running the series. But I thought the setup was worth jotting down, in case anyone else thought they could make use of the concept in their own game.
