I think I have been cheating. I have done this twice now and have been able to pinpoint where I was (I was too lazy to go back to where I started but it was within a mile). I have been reading the signs as I go down the road and then use google. The first time I went past a post office that said I was in some town in North Dakota. The second time, there was an ad for a politician on the back of the truck. Googling that put me a Sinaloa Mexico. Going down the road a little further got me got me to a restaurant which has a facebook account with the Sinaloa street address and a picture for confirmation.
hehe.....i drew the line at -googling- the info i found....so i read signs..etc...but if i couldn't tell based on those...a more precise place...i went with what i could tell