Is it possible to plot your own route on the Maps app on an iPhone/iTouch?

I was curious about the distance between two locations so I put them both in on Maps and it gave me the shortest distance. The thing is, because a couple of those roads aren't safe to walk on, I take a different route. I'd like to know the distance from point A to B on the route I normally take each day but I don't know how or if it's even possible to set up that route on Maps on my iTouch to see the distance. So is it possible for me to do it?