+1 for mapmyrun. It gives you a lot of information such as the gradient of any road, so you'll know if you're running up or down hill before setting out (this was super helpful when I was on holiday in the alps during my marathon training...didn't want to find myself running up a mountain!).
Have you tried driving out on a route before running it? That way you'll get a feel for the level of traffic along that road.
I run both in inner city during the week and in countryside at weekends. to make it safer (there are no pavements and some roads are very tiny), I make sure that whatever the weather or time of day, I'm wearing visible clothing. I run on the same side of the road as on coming traffic (amazing how many people don't!). I don't wear headphones, so that I can hear any on coming traffic (usually hear it before I see it).