Funny how a lot of people think that being a cargo pilot is like a stepping stone to the more "prestige" passenger flying. How wrong they are. Cargo pilots with UPS and Fedex are amongs the highest paid pilots in the world. Average annual salary of UPS pilots in 2004 was appx. $175,000. And they have just signed a new contract, a 12 year Captain will received appx. $45K for signing bonus. Not a bad chunk of change on top the nice pay raise. And for the majority of other carriers, cargo pilots get the same payscale as the pax drivers and for some you do fly both types.
IMHO, being a freight dog is the best kept secret in aviation. No pax, no shirt, no tie (sweat shirts and pants on the a/c are the norm), no dragging bags through the terminal (yes, and since there or 2 or 3 of us, at certain port of calls, we do get limo-ed to and from airport in S-class Benz. That's right, no crew van with the noisey hosties.) and not too mention excellent catering (at certain places, we do get catered from a local restaurant and you get to pick what you want to eat. Yup, no airline food.) And the hosties are way overrated especially here in the US (longhual types).
As far as days and nights go, these days longhuals are so long that you will see both night and day in a single trip regardless of when you become airborne anyhow.
Flying pax? not me but thanks for asking.