how long as usual depends... are you modifying the original steering column or going aftermarket? If modifying are you also adding the horn button kit, also is it a floor shift or column shift? How rusted are your fasteners? Do you have a pitman arm or gear puller? Do you have a steering wheel puller?
Mine, using the Toyota box took a weekend, several hours of that was fighting with getting the OEM pitman shaft nut and arm off the Toyota box. I would highly recommend taking off the driver's side inner fender panel at least for ease of access. Put the front axle on jack stands so you can swing the spindle back and forth. Rebuild the drag link ends and replace the grease seals, check the ball on the steering arm for wear, replace if shows any wear. Replace the tie rod with the heavy duty one from MF. If using the stock springs add one set of caster shims between the springs and axle so the axle top tips back more (increased caster). If using lowering springs or have removed leafs to lower add two shims on each side (two shims will likely require using spring centerbolt with longer head.)