Other than being a bit wide for some of the more precarious mountain trails I've been on, the 78-79 is quite capable. Try some of the narrow trails in the Smokies or even the Ozarks and you will find out quickly why folks warn about the girth of these trucks. Keep in mind that the 78-79 bodies "hang over" their axles even more than their later model cousins do. I've been on mountain trails where I've had to back up more than a half mile because my full-size 93 (which is comparatively narrower than the 78-9 models) was too wide for a smaller rig coming the other way to get around. I've also spent several minutes with six grown men clinging to the passenger front corner to keep the driver's rear from slipping off a 100' drop. Its precarious... even if you are used to it.