Okay, Salem is NOT on any real highway, so you have a couple of options for getting there. Head north out of Logan or the car rental agency, on Route 1A. Bear slightly left at the rotary/roundabout you can drive through. 1A turns into Route 60.
After a couple of miles, youll come to a small rotary/roundabout. DRIVE CAREFULLY ¾ of the way around it, onto Route 107 North. Youll drive through Saugus/Lynn Marsh, then the city of Lynn (lots of traffic lights) then into Salem.
Or, go halfway around that rotary/roundabout, then about two more miles and take Route 1 north. If its after 2 PM on a weekday, merge CAREFULLY into traffic. Drive about eight miles, then take Route 95/128 north for about two miles, stay in the middle lane so when the two highways split youll be on the correct one (128). Take exit 25A or 23S and follow the signs to Salem.
Um, where are you staying?