RIFTS is a tabletop role-playing game that professes the capacity to play whatever you can imagine. While the reality of this is less than the imagery created by the advertising copy, this is not false; it just takes some work to make it viable at the able. With that in mind, let us take a moment to talk about doing that.
There is a difference between "crossing the streams" (a campaign that melds two or more archetypical campaign models together) and a kitchen sink game where anything goes no matter the sensibility of it. We want the former, and not the latter, so we are not sloughing off the necessary work that running a campaign entails. Instead, we are changing what the workload is and the order of operations.
No, no handy media example this week. Now I'm making you do your own research. Hop to it, and get used to doing it; that's what it takes to make the pre-game work of a GM into something useful at the table.