My wife and I decided to build a tandem for our three year wedding anniversary.

Neither of us are expert bike mechanics and we know a decent amount about bikes, but we aren't super geniuses when it comes to this sort of thing. We've been researching components over the last few months and the pinnacle of our setup will be a Rohloff Speedhub, no derailers will be on this bike.

The last group of things we need to decide on is a crankset and everything that goes with it (pedals, cranks, bottom brackets, chainrings, chain, etc.).

I'm having a somewhat difficult time figuring out what our options are. Seems like you can buy a complete 24/27 speed setup for a pretty penny, or you can buy individual components, but I'm not familiar enough with the unique nature of tandem cranks to be completely comfortable with that.*

Considering the derailerlessness, what should I be looking for?

The tandem will be used for 30-70 mile day rides on paved paths initially, and eventually for touring.