I've got newer batteries, and glow plugs; so no issues with cold starts(within the last few years). The average high here in the winter is usually around 30*, often times in the teens. I remember growing up in Texas, and my dad putting cardboard in the radiator. I remember a lot of folks down there doing that, but up here, where it's colder, I don't see too many people, even with these older trucks doing that, just odd. Mine's never given me any problems heating up in the cold.
The truck along with everything else, if left for a couple weeks, runs the risk of the batteries draining in this cold. The Caveat to that though, is the fact of having lived in Arizona, the heat will do the same thing to batteries; zap'em.