The most direct route would be go east to Gaspar Hernandez and when you get to the big T intersection with the gas station/carwash make a right and that road will take you thru the mountains and you will come out in Tenares and from there its a short hop over to Salcedo, The only problem is I havent done this road in a few years so I am not sure of its condition today. I used to do it with a jeep and the road was bad in spots back then but definately passable.
The other route that I would suggest would be east past Caberette then make the right turn going to Jamao Norte. Continue thru the mountains till you come to a T intersection with a nativa gas station, make a left turn then continue on till you enter Moca go straight till you come up a hill with a jail on your left and another T intersection, make a left there and you keep going straight and you will be on your way to Salcedo.