Use the landscape to help you, noise from the roads in valleys goes upwa=

rds, but you can use a "shoulder" (not human - I mean a land contour) to pr=
otect you from it. You have a car so study maps (1:25,000 at least) to find=
 access to minor valleys away from the main arteries, there you can be most=
 sheltered and it is quietest. Avoid or get away from the cols (mountain pa=
sses) - the motorcyclists love them. You can often park at the top of a col=
 but then you need to walk 30 mins or more around the contours or on a ridg=
e trail to get away from the noise. I find it nice to get up there early mo=
rning, take food and drink, then simply walk with my gear in a pack and set=
 up wherever I find a good spot, you can go all day like that.