Well, with the death of the Prelude forum, which was admittedly necessary to kill, there have been no non-faction preludes. So my recommendation is that you pre-make a few prelude maps, and during the first week of each RL month, Run a single prelude. An escape from Undermountain one, escape from slavery ones, Just basic ones to add a little flavor.
Just, Of course, a suggestion, -Heltec