I have a look on google maps before taking a trip i haven't done before, that way i can see major landmarks etc. I think written directions are better as you know what to look for in advance, a sat nav cant do this. I live in the south east and if i was to follow my sat nav directions i would spend most of my time parked on a motorway. Local knowledge tells me the M25 M23 M3 and M4 are to be avoided, the estimated time on the sat nav is quicker but in reality can take hours longer.

Dave